Documents published in 2024 : Scipedia

Open-source implementation of the new unified CPT-based axial method in sands
C. Sastre Jurado, B. Stuyts*

ISC2024.

Abstract
This paper presents the implementation into the open-source finite element simulation framework OpenSees of the new Unified CPT-based method for driven piles in sands. The formulation incorporates the maximum skin friction and endbearing CPT values based on the new ISO-19901-4 under development, within the non-linear load-transfer curves calibrated against the measured responses from the static pile tests in the unified database. Special attention was paid to maintaining an open-source philosophy during the implementation. The important EURIPIDES research tests in highly dense sands are considered as a worked example to illustrate the application of the implemented method. The numerical benchmark shows good agreement between the model and full-scale measurements.
Abstract
This paper presents the implementation into the open-source finite element simulation framework OpenSees of the new Unified CPT-based method for driven piles in sands. The [...]
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Comparison of Different Prediction Methods to Derive Synthetic CPT Profiles - An Offshore Wind Farm Case Study from the German North Sea
L. Siemann*, P. Masoudi, R. Maraka, R. Opris, Y. Pande, N. Römer-Stange, N. Morales, T. Mörz

ISC2024.

Abstract
The further development of offshore windfarm areas in various countries plays a key role in the transition of energy production towards renewable sources. As offshore windfarm areas tend to expand and the amount of ground truth data is limited, the estimation of geotechnical parameters at unknown locations integrating other site investigation data becomes a necessary tool. This is especially relevant for cost efficient area wide site characterization. Here, the proper integration and correlation of geotechnical and geophysical data is a key factor for reliable ground model building. This study investigates different prediction methods, while presenting a modelling framework which incorporates geological, geotechnical, and geophysical information to derive synthetic Cone Penetration Testing (CPT) profiles using offshore windfarm site investigation data from the German North Sea. We combine geological interpretation, CPT data and 2D ultra high-resolution seismic reflection data. The geophysical and geological information are used to guide geotechnical parameter prediction. Additionally, seismic horizons constrain the prediction as structural information. For evaluation, we test and compare several prediction techniques, with different level of complexity, from geostatistical methods to machine learning. Seismic attributes are used as auxiliary information to improve CPT parameter prediction. To validate the results, CPT parameters are predicted onto a representative 2D seismic line and a leave-one-out cross-validation (blindtest) is performed. Though all methods struggle to replicate local extremes, results indicate a reduction of prediction uncertainty when implementing seismic attributes.
Abstract
The further development of offshore windfarm areas in various countries plays a key role in the transition of energy production towards renewable sources. As offshore windfarm [...]
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AI-Based Digitization of Legacy Ground Information
J. Llopart*, P. Behjati, I. Aliguer

ISC2024.

Abstract
Geotechnical characterization of site materials is of paramount importance in the construction and mining industry. The analysis of large volumes of geotechnical information from multiple sources leads to data-driven decisions that help to minimize uncertainty. For this purpose, a unified digital information platform becomes handy to have a global perspective and improve the analysis of available ground information data. Access to historic ground investigation data from previous projects during the project planning stage might increase efficiency. However, accessing and processing legacy data from companies’ databases is time and resources consuming. In the recent years, software tools that are capable of extracting data in a digital format from images have become popular, but still require human-supervised interpretation. A novel tool combining Optical Character Recognition (OCR), digital data extraction technologies and AI-based data interpretation system is presented herein. The state-of-the-art OCR technology is capable of accurately recognizing and extracting text from various document types, such as scanned documents, images, and PDFs. It utilizes advanced machine learning algorithms to process text, even in challenging conditions, ensuring data is extracted accurately and reliably. Then, a data interpretation system has been trained to identify the type of site characterization data and its structure while retrieving all the content in a digital format. All components work seamlessly together to provide a comprehensive solution for automating the interpretation and extraction of site characterization data, streamlining data management and analysis processes. The capability of gathering data from multiple sources in a unique ground information system provides valuable information for planning and design stages while decreasing costs, time and uncertainties. In addition, all these data are then available within DAARWIN platform to feed the ground model workflow.
Abstract
Geotechnical characterization of site materials is of paramount importance in the construction and mining industry. The analysis of large volumes of geotechnical information [...]
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Direct-Push Profiling Technologies for Sustainable Investigation of Contaminated Sites
J. García-Rincón*

ISC2024.

Abstract
Most contaminated site investigations still rely on conventional characterisation approaches based on collecting a limited number of soil samples and installing long-screened wells. However, it is widely recognised that these methods cannot adequately capture the subsurface heterogeneity largely governing the fate and transport of contaminants. Following the example of cone penetration testing (CPT), multiple direct-push profiling tools have been developed over the years to investigate and manage contaminated sites in a more efficient and sustainable way. The objective of this work is to present well-established and emerging direct sensing technologies for contaminated site investigation and demonstrate how their application does not just result in a reduction of uncertainties but also in improved sustainability outcomes. The assessed technologies included the Hydraulic Profiling Tool (HPT), laser-induced fluorescence (LIF), Membrane-Interface Probe (MIP), and nuclear magnetic resonance (NMR). Direct-push profiling techniques were found to be valuable throughout the project lifecycle, from initial site screening phases to remedial design and closure. The high-density data collected helped to delineate contaminant source zones, preferential migration pathways and low-permeability zones. This information complemented the analysis of a reduced number of physical samples to optimise remedial designs and monitoring networks. Additional benefits related to sustainability concepts included the production of minimal investigation-derived waste, the need for less field campaigns and the little impact caused to site owners and their activities. High-resolution site characterisation approaches are paramount to conduct informed risk assessments and effectively achieve remediation goals.
Abstract
Most contaminated site investigations still rely on conventional characterisation approaches based on collecting a limited number of soil samples and installing long-screened [...]
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Advances in the Characterisation of Sites Contaminated with Petroleum Hydrocarbons: Insights from a Collaborative Effort
J. García-Rincón*, E. Atekwana, E. Gatsios, R. Lenhard, R. Naidu

ISC2024.

Abstract
Petroleum hydrocarbons (PHCs) such as gasoline and diesel are among the most common and widespread contaminants in urban and industrial environments. The authors were engaged by the imprint Springer to complete a book giving visibility to technologies overcoming limitations associated with conventional characterisation approaches, as well as pertinent concepts and methods that may still be underutilised by the industry internationally. The open access book entitled ‘Advances in the characterisation and remediation of sites contaminated with petroleum hydrocarbons’ was prepared as a contributed volume involving the participation of more than 100 global experts from academia, government agencies, and the private sector. An analysis of the book contents yielded general insights into the state of the art regarding the investigation of PHC-impacted sites. As highlighted in several chapters, fate and transport of fuel products are controlled by multiphase flow mechanics and constitutive relations intrinsically linked to biological phenomena and the spatial and temporal variability of multiple subsurface properties. Most site characterization methods presented in the book (from direct-push vertical profiling and biogeophysics to sequence stratigraphy or molecular biological tools) address aspects often overlooked in conventional site investigation projects, including: (i) the entrapment of fuel products due to capillary forces, (ii) the essential role played by microbial activity, and (iii) subsurface heterogeneity effects. Further research and adoption of up-to-date concepts and methods are encouraged to ensure best practices are implemented and PHC risks are managed sustainably and responsibly
Abstract
Petroleum hydrocarbons (PHCs) such as gasoline and diesel are among the most common and widespread contaminants in urban and industrial environments. The authors were engaged [...]
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Towards An Integrated And Automated Digital Workflow In Geotechnical Engineering
R. Brinkgreve*, A. Zekri, A. Laera

ISC2024.

Abstract
The use of soil data is essential in geotechnical design, but in a preliminary project phase such data are usually limited to that inferred from field tests, like CPT, SPT or DMT. In previous publications by the authors and co-workers, it was shown how such data can be automatically processed into soil profiles and parameter sets for geotechnical finite element analysis. Another publication demonstrated the automated processing and creation of geological models as an intermediate step to more advanced 3D geotechnical modelling in a BIM / Digital Twin environment, which facilitates the link with other disciplines and stakeholders in a project. The major challenge of connecting layers across multiple 1D boreholes to form 3D soil layers is overcome by using a Machine Learning clustering algorithm. As a next step, the previously introduced Automated Parameter Determination (APD) method (connecting correlations using Graph theory) is applied based on averaged CPT parameters from all contributing layer sections. The result is an automated system that creates a complete 2D or 3D finite element model, including constitutive model parameters, for geotechnical analysis purposes. An automated system may be very efficient when exploring different design alternatives in an early stage of a project. However, it is important to emphasize the role and responsibilities of the geotechnical engineer in the design process, which requires the system to be transparent, verifiable, and adaptable. This paper describes the state-of-the-art of this ongoing research project.
Abstract
The use of soil data is essential in geotechnical design, but in a preliminary project phase such data are usually limited to that inferred from field tests, like CPT, SPT [...]
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Data-driven site characterization - Focus on small-strain stiffness
H. Felic, I. Marzouk, F. Tschuchnigg, T. Peterstorfer

ISC2024.

Abstract
Non-linear soil behaviour adds complexity in accurate parameter selection for numerical modelling. One of these parameters is the small-strain shear stiffness. This parameter depends strongly on the soil mass density and the shear wave velocity; the latter can be determined through in-situ tests or laboratory tests. The paper focuses on training various machine learning models to predict shear wave velocity estimates based on raw data from cone penetration test soundings. Three decision tree algorithms are considered for the analysis: XGBRegressor, HistGradientRegressor, and RandomForest. Various data preprocessing approaches are investigated, including noise removal and outlier identification, to assess their impact on the model performance. The results indicate that different data preprocessing approaches yield significant differences in the model performances. When applied to unseen raw data from a sand site of the Norwegian GeoTest Site, the model demonstrates promising predictive capabilities and is in a good agreement with well-known correlations. This study underlines the importance of data quality and preprocessing for reliable machine learning models. To enhance transparency and reproducibility, a GitHub repository with all the used files is made available online.
Abstract
Non-linear soil behaviour adds complexity in accurate parameter selection for numerical modelling. One of these parameters is the small-strain shear stiffness. This parameter [...]
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Effect of Precast Pile Driving on Liquefaction Potential Mitigation of Sandy Silts Based on CPTu
K. Fakharian*, F. Kaviani-Hamedani, M. Bahrami, H. Vaezian, I. Attar, M. Hashemi, A. Osouli, T. Bahrami

ISC2024.

Abstract
Precast concrete piles are adopted as a foundation solution in liquefiable silty sand and sandy silt layers of north of Oman Sea shorelines for large diameter liquid tanks. The ground water table is about 6 m deep, and a highly potential liquefiable layer is identified from 7 m and continues to about 12 m deep. This liquefiable layer not only reduces the pile shaft skin friction, but also could have caused damage to slender precast piles as a result of kinematic and inertia shear forces and bending moments, in particular at the intersection of liquefiable and non-liquefiable cohesive layers underneath. The main objective of the paper is to evaluate the effect of densification of sandy silt deposits attributed to pile installation and the possibility of liquefaction mitigation effects due to radial compaction of the soil. CPTu tests were carried out prior to and after the installation of piles. It is noticed that both qc and fs were increased depending on the center-to-center spacing of piles. Liquefaction analysis is carried out on CPTu results before and after piling installation and it is observed that the sandy silt layers are significantly strengthened against liquefaction and the safety factor notably rose above unity after the pile driving operation. The results are compared with triaxial cyclic tests on samples taken from a comparable depth for further investigation, indicating that the mitigation has occurred simply with a 10 percent increase in the relative density of the liquefiable sandy silt layer
Abstract
Precast concrete piles are adopted as a foundation solution in liquefiable silty sand and sandy silt layers of north of Oman Sea shorelines for large diameter liquid tanks. [...]
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Characterization of the Consolidation Coefficient Behavior from Piezocone and Piezoball Tests in a Brazilian Soft Soil
J. Sosnoski*, A. Meier, G. Dienstmann, H. Nierwinski, E. Odebrecht, F. Mantaras

ISC2024.

Abstract
The present paper aims to validate the applicability of a piezoball test equipped with pressure transducers at the probe’s tip, middle, and equator faces to estimate the coefficient consolidation behavior of a soft soil deposit. The proposals of Mahmoodzadeh et al. (2015) and Liu et al. (2023), derived from numerical solutions, can be adopted to estimate horizontal coefficients of consolidation (ch) through the piezoball dissipation measurements. The dissipations tests were performed at depths of 4, 6, 8, and 10 m and were conducted up to at least about 70% of dissipation of the excess pressure generated during the penetration, except for the test at a depth of 4m, done at 85%. Results were directly compared with piezocone, and the estimated values for the consolidation coefficient were similar for all methodologies applied, both at the face and equator positions.
Abstract
The present paper aims to validate the applicability of a piezoball test equipped with pressure transducers at the probe’s tip, middle, and equator faces to estimate the [...]
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The Use Of Large-Scale 3D Numerical Modeling to Identify Areas of Increased Seismic Risk in Polish Underground Copper Mines.
K. Fuławka*, L. Stolecki, I. Jaśkiewicz-Proć, R. Kołodziej

ISC2024.

Abstract
Seismic activity and related rockbursts are currently one of the most dangerous threats negatively affecting work safety and continuity of operation in Polish underground copper mines. Taking into account the experience to date, it can be clearly stated that current technical and organizational tools do not make it possible to eliminate mining tremors, however, by taking appropriate actions, it is possible to minimize the threat and partially control it, e.g. by active de-stressing the rock mass. However, developing an appropriate schedule of preventive activities is still a burning issue. This is due to the random nature of mining-induced seismic phenomena which makes it impossible to accurately predict the place, energy and time of the seismic event. A breakthrough could be the use of stage-based large-scale numerical modelling based on which it would be possible to track stress changes with ongoing exploitation and locate areas of increased seismic risk. This study presents the results of large-scale three-dimensional FEM-based numerical modelling enabling tracking of changes in stress distribution with the progress of exploitation. Then stress distribution and areas identified as prone to instability occurrence were correlated with the areas of high-energy seismic tremors manifestation. Models were prepared at monthly intervals, and validated with the use of measurements obtained with underground geomechanical monitoring systems. As preliminary analyses show, well-validated numerical models can be the basis for estimating seismic risk and may be useful at the stage of designing methods for preventing active rockbursts and seismicity prevention.
Abstract
Seismic activity and related rockbursts are currently one of the most dangerous threats negatively affecting work safety and continuity of operation in Polish underground [...]
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A Data-Driven Approach to Predict Shear Wave Velocity from CPTu Measurements: An Update
I. Entezari*, J. Sharp, P. Mayne

ISC2024.

Abstract
This paper is an extension of our previous research investigating the potential of machine learning models to estimate shear wave velocity (Vs) from piezocone penetration test (CPTu) measurements. The aim of this update is to examine the effect of incorporating geographical information, namely latitude and longitude, as input parameters to the machine learning models. New models are developed by incorporating both CPTu parameters and spatial coordinates as input features and are compared to models developed with only CPTu parameters. Furthermore, SHAP (SHapley Additive exPlanations) analysis is employed to assess the importance of different features and variables in the developed machine learning models. The results show improvement in prediction performance when adding geographical data, indicating the influence of geological variations on Vs. The paper shows the potential of using geospatial information to improve the data-driven approach for estimating soil properties from CPTu tests when large worldwide datasets are available.
Abstract
This paper is an extension of our previous research investigating the potential of machine learning models to estimate shear wave velocity (Vs) from piezocone penetration [...]
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A Data Driven CPTu-PINNs Method to Predict Soil Settlement
H. Li, Z. Ouyang*

ISC2024.

Abstract
Obtaining soil parameters through laboratory tests and solving the governing equations that describe soil settlement can be time-consuming, making immediate on-site predictions of soil settlement challenging. In-situ testing provides a more efficient approach to obtain soil parameters than laboratory tests. Data from the Piezocone penetration test (CPTu) can be used for on-the-spot interpretation of soil mechanical parameters, which can then be incorporated into the governing equations for soil settlement calculation. Physics Informed Neural Networks (PINNs) algorithm uses automatic differentiation method to directly embed partial differential equations (PDEs) into a deep learning neural network and provides solution for these PDEs in a cost-effective manner compared to traditional numerical methods. In this paper, a framework integrating data from CPTu and PINNs to predict soil settlement is proposed and evaluated through comparison with numerical simulations from Finite Element Methods (FEMs). Results show that the framework gave a reasonably good agreement with the FEMs benchmark while substantially reduced the computation time. This method allows for immediate on-site prediction of soil settlement during site investigations, thus better guiding surveying and construction activities.
Abstract
Obtaining soil parameters through laboratory tests and solving the governing equations that describe soil settlement can be time-consuming, making immediate on-site predictions [...]
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Can Seabed Spatial Uncertainty Be Quantified Using Advanced Statistical Approaches?
J. Valderrama*, M. O'Neill, F. Bransby, P. Watson, M. Bertolacci, A. Zammit-Mangion

ISC2024.

Abstract
Knowledge of seabed properties away from investigated locations is often required, for example, when geotechnical surveys are sparse or when the field layout changes between investigation and construction phases. In such cases, design lines that appropriately incorporate the uncertainty of the seabed properties must be defined to ensure reliable (yet not overly costly) design. This paper explores how two different approaches, traditional engineering judgement and advanced statistical methods, fare at quantifying the uncertainty of a real offshore site. This is achieved by ‘hiding’ different data and ‘scoring’ the predictive performance of the methods against a range of criteria. The work reveals that complex geological sites are significantly more challenging to represent than the stationary random fields often examined in research and suggests that more advanced approaches incorporating broader data sets are required to reduce uncertainty.
Abstract
Knowledge of seabed properties away from investigated locations is often required, for example, when geotechnical surveys are sparse or when the field layout changes between [...]
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Soil Variability From High-Resolution S-Wave Full-Waveform Inversion: Deriving Reliable Cone-Tip Resistance From Vs for Geotechnical Evaluations
E. Revelo-Obando*, R. Ghose, M. Hicks

ISC2024.

Abstract
Capturing the spatial variability in soil is crucial for ground response analyses in the context of seismic hazard mitigation. The lateral variability in thickness and properties of the different soil layers is one of the main factors that determines the variability of the ground motion spectrum from one location to another. The absence of such lateral variability information in the subsoil in between the locations of Cone Penetration Tests (CPTs) may be compensated by the use of more densely sampled seismic data. In this research we aim to derive a shear-wave velocity field through seismic full-waveform inversion that yields a model resolution approaching that of high-resolution seismic CPT surveys. Following this, a datadriven correlation between geophysical and geotechnical information is attempted through the application of new machine-learning-based approaches.
Abstract
Capturing the spatial variability in soil is crucial for ground response analyses in the context of seismic hazard mitigation. The lateral variability in thickness and properties [...]
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Stress History and Effective Shear Strength Parameters Evaluation of a Dilative Stiff Clay
G. Pinto*, M. Araujo, A. Faria, J. Carneiro, M. Junior

ISC2024.

Abstract
The Cone Penetration Test (CPTu) can be used to evaluate the soil behaviour and properties through correlations (empirical and/or analytical), and the results must be compared to laboratory tests to be validated. This paper presents the evaluation of the effective friction angle (φ’) of a stiff over-consolidated Brazilian clay based on CPTu data and laboratory tests characterization, such as index properties, and the comparison of the effective shear strength parameters obtained by triaxial tests. Based on CPTu data, the soil was classified using the Soil-Behaviour Type Classification System (SBTn) proposed by Robertson (2016), and properties such as over-consolidation ratio (OCR) and the effective friction angle were determined using well-known correlations such as Chen & Mayne (1996) and Ouyang & Mayne (2019). The shear response defined by CPTu was compared to the results of isotropic consolidated triaxial compression tests (CIUC). The results showed mainly a clay-like behaviour based on the CPTu data, in agreement with the laboratory characterization, which indicated high plasticity. Regarding the shear response, both the triaxial test and the CPTu data indicated dilative behaviour under shear. Furthermore, the effective friction angle obtained from the triaxial test and the CPTu data were similar depending on the OCR used in the equation, demonstrating the applicability of the adopted methodologies for the Brazilian stiff over-consolidated clay. Finally, based on CPTu data it is proposed a complement of the SBTn developed by Robertson (2016) with OCR isolines.
Abstract
The Cone Penetration Test (CPTu) can be used to evaluate the soil behaviour and properties through correlations (empirical and/or analytical), and the results must be compared [...]
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Numerical and experimental assessment of steering forces during horizontal penetration in sand – a validation of a bio-inspired optimal tip shape
F. Patino-Ramírez*, J. Salomon, Y. Yang, A. Holmes, C. O’Sullivan

ISC2024.

Abstract
The exploration, characterisation, and monitoring of the subsurface is relevant to a wide range of applications, from environmental monitoring and in-situ characterisation to infrastructure construction (e.g., directional drilling and tunnelling) and resource withdrawal. Bio-inspiration offers promising solutions to overcome two of the most important challenges in the development of autonomous subsurface exploration probes: exploration range (related to drag forces) and steerability (i.e., ability to control direction of movement). The work uses a previously proposed bio-inspired intruder shape to study the relationship between tip orientation and the resulting forces (lateral and vertical); and explores the idea that these forces can be used to steer the probe, i.e., control the direction of motion of the probe as it advances. Numerical results with the discrete element method and experimental results with a large-scale test bed show a direct relation between tip orientation and the steering (lift and lateral) forces – supporting the case for steering systems based on intruder tip rotation. In the results, lateral and vertical forces also show a strong relation with tip orientation, however, for the tip shape tested, the vertical forces are limited to the neutral to upwards range (i.e., towards the free surface). Experimental results evidence the significant effect of intruder deformation (bending) and/or path deviation in the penetration forces acting on the intruder.
Abstract
The exploration, characterisation, and monitoring of the subsurface is relevant to a wide range of applications, from environmental monitoring and in-situ characterisation [...]
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Particle Crushing and Liquefaction Resistance of Crushable Aragonite Sands
M. Saqib*, A. Das, N. Ranjan, P. Patra

ISC2024.

Abstract
The influence of soil crushability on the strength parameters of aragonite sand under cyclic undrained conditions is investigated in this study. The investigation used aragonite sand, which is known for being susceptible to crushing under normal loading conditions. A series of cyclic simple shear tests were carried out at different normal loads of 100kPa, 150kPa, 200kPa, and 250kPa under a constant confining pressure. To maintain consistency in particle crushing, sieving tests were used to assess the level of particle breaking, with testing stopping after a predetermined number of cycles. The results show that particle crushing increased the fines content of the soil, even when the effective stress was low during the undrained shear phase. The liquefaction resistance of aragonite sands increased as normal load increased. These findings show the major influence of soil crushability on the engineering behavior of aragonite sand, implying that conventional assumptions about the link between normal load and liquefaction resistance may not be true for crushable soils.
Abstract
The influence of soil crushability on the strength parameters of aragonite sand under cyclic undrained conditions is investigated in this study. The investigation used aragonite [...]
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Hydraulic Profiling Tool for Groundwater Vulnerability Assessment at an MSW Landfill
P. Singh*, D. Haritwal, G. Ramana, M. Datta

ISC2024.

Abstract
Characterization of the unsaturated zone below an MSW landfill is critical to evaluate the groundwater pollution vulnerability assessment. The permeability of the soil in the unsaturated zone, the depth of the water table, and the quality of pore water in the soil can provide a reliable site-specific estimate of pollution vulnerability. To evaluate these factors, an attempt was made to use the hydraulic profiling tool (HPT) in the unsaturated zone below a non-engineered MSW landfill in Delhi. HPT was equipped with an injection logger capable of qualitatively measuring permeability at the cm scale and an electrical conductivity (EC) dipole that measures the bulk soil conductivity. HPT findings were compared with piezocone penetration tests (CPTu) and the electrical conductivity of extracted pore water from the soil cores. The results indicate that pressure from the injection logger works effectively for medium/fine sand and silt and has greater sensitivity to permeability changes for these soils than CPTu. Pore-water EC was found to have a good correlation with volumetric water content and EC from HPT. A groundwater vulnerability matrix was conceptualized using factors based on the time of leachate travel and maximum pore-water EC observed, both derived from HPT, and risk scores were assigned from 1-5, corresponding to the 9 zones of the matrix. The locations surveyed at the dumpsite received scores of 4 and 5, which depicts high vulnerability. The results indicate that HPT can be used for rapid site-specific groundwater vulnerability assessments.
Abstract
Characterization of the unsaturated zone below an MSW landfill is critical to evaluate the groundwater pollution vulnerability assessment. The permeability of the soil in [...]
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Comparison Between Eggshell Lime and Commercial Lime as a Soil Stabilizing Agent
B. Meneguz, H. Nierwinski, B. Caetani*

ISC2024.

Abstract
Reducing the extraction of natural resources is a current demand in the construction industry. Studies show that eggshells are rich in calcium carbonate and have the potential to replace limestone in lime production. In this context, the objective of this article is to use an eggshell lime produced in the laboratory to stabilize a residual clayey soil and compare the unconfined strength of the admixtures with others using commercial dolomitic lime. Different lime contents and porosities were evaluated and the porosity/lime ratio was studied to understand the unconfined strength behavior of admixtures. In addition to the soil and limes characterization tests, X-ray diffraction tests were carried out to analyze the chemical and mineralogical composition of the materials. The results showed that increasing lime content and decreasing porosity increased unconfined strength. Also, the unconfined strength achieved with the eggshell lime was greater than that achieved with dolomitic lime for the same lime content. The X-ray diffraction tests showed that the eggshell lime is composed almost entirely of calcium hydroxide, and microscopic images demonstrated much stronger bonds in the final product obtained from eggshell lime. The porosity/lime ratio was a good parameter for evaluating unconfined strength. A unique relationship was achieved linking unconfined compressive strength with the porosity/lime ratio for both the eggshell and the dolomitic lime mixtures.
Abstract
Reducing the extraction of natural resources is a current demand in the construction industry. Studies show that eggshells are rich in calcium carbonate and have the potential [...]
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Considerations on the site characterization of tropical soils by in situ tests
B. Rocha, R. Rodrigues, H. Giacheti*

ISC2024.

Abstract
The fundamentals for predicting the mechanical behavior of soils by in situ tests have been developed for conventional soils (either clay or sand) based on the stress history. The behavior of unusual geomaterials, such as the tropical soils, is characterized by bonding and structure, anisotropy as well as by the unsaturated condition. The behavior of tropical soils cannot be correctly predicted by models and correlations developed by the Classical Soil Mechanics. This paper presents the fundamentals of the behavioral classifications used to interpret CPT and SDMT and discusses their applicability to tropical soils, especially those of pedogenetic evolution of sandstone. Laboratory and in situ tests (CPTu and SDMT) were carried out at two research sites in São Paulo state, Brazil, at different periods of the year to better understand the soil behavior and the seasonal effects. Classifications and correlations to estimate soil parameters from CPTu and SDMT are assessed. Interrelationships between elastic parameters of small (G0) and large to medium strain parameters (qc, ED, MDMT) determined by in situ tests are presented to identify the presence of microstructure and unusual soil behavior. Classification criteria based on these relationships to identify collapsible soils also is presented
Abstract
The fundamentals for predicting the mechanical behavior of soils by in situ tests have been developed for conventional soils (either clay or sand) based on the stress history. [...]
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Drainage Effects in a Dilatant Carbonate Silty Sand
F. Farzaneganpour, F. Bransby*, C. O’Loughlin

ISC2024.

Abstract
This paper presents and discusses results from a series of cone, vane and footing tests in a carbonate silty sand, conducted in a geotechnical centrifuge, that investigate how drainage effects scale with the diameter of the device/foundation. The tests involved different penetration and rotational velocities to quantify how velocity influences the drainage response, and in turn, the magnitude of the deduced soil strength. Cone and foundation resistance, and the shear stress measured in the vane tests, were seen to increase with increasing penetration/rotational velocity, consistent with a dilatant shearing response. The collective dataset is interpreted within the ‘drainage backbone curve’ framework, with an attempt made to understand how drainage path length varies for the different devices and is affected by stress level.
Abstract
This paper presents and discusses results from a series of cone, vane and footing tests in a carbonate silty sand, conducted in a geotechnical centrifuge, that investigate [...]
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Site characterisation, data management and data integration for submarine cable landing Projects
V. Terente, D. HIxman, H. Waterson, M. Wetton*

ISC2024.

Abstract
There is an increased need for submarine cable infrastructure across the world to serve the offshore wind power industry and the expansion of the submarine interconnectors and telecommunication networks. Cable landfall projects are complex as land, intertidal, nearshore, and offshore environments all coverage, creating an array of dynamic processes, constraints, hazards, and engineering challenges that an asset may face over its lifespan. Robust site characterisation and ground modelling is key for the success of these projects, to allow for the effective, safe, and economical site selection, design, installation, and operation of an asset. In order to accomplish this, the integration of engineering and geoscientific datasets, obtained through several data sources and survey techniques is required; as well as collaboration and integration between multiple technical disciplines. This paper lists the key stages, techniques, and sources available for obtaining the required data. We then consider how the data can be managed and integrated to obtain a holistic ground model for use in the design, construction, and operation of the asset. We discuss the value these models can provide throughout the lifecycle of landfall projects.
Abstract
There is an increased need for submarine cable infrastructure across the world to serve the offshore wind power industry and the expansion of the submarine interconnectors [...]
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Nanotechnology Applied for Soil Stabilization - a Survey
B. de Córdova Caetani*, H. Nierwinski, B. Karasiak Meneguz

ISC2024.

Abstract
The technical and constructive challenges inherent to the execution of engineering works on problematic soils require a continuous development or improvement of the techniques and methods used to investigate the soils’ behavior and to design and evaluate the performance of these works. Soil stabilization is one of the most used techniques to improve the mechanical behavior of the soil. In addition to classic soil stabilization methods, nanotechnology is increasingly being used for various purposes, such as introducing nanoparticles of different compounds into the soil mixture or in the field of geosynthetics for fiber treatment. Although they do not have cementing properties, nanoparticles improve mechanical properties, thermal stability, and physicochemical behavior. Studies carried out with different types of soil show that introducing nanoparticles into the soil-cement matrix reduces the space between particles and provides a more robust and rigid soil skeleton. Considering this, it improves the material's resistance properties and reduces cement consumption, contributing to sustainability. The literature review presents research that evaluates different nanoparticles applied to soil mixtures and their influence on the final product. This paper reviews the state of the art of several studies showing that nanotechnology is a successful solution that can be used in soil stabilization because of its capacity to improve, for example, shear strength, unconfined compression strength, and the elastic modulus of soil. The research gap and prospects for using nanotechnology for soil stabilization are also exposed.
Abstract
The technical and constructive challenges inherent to the execution of engineering works on problematic soils require a continuous development or improvement of the techniques [...]
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Organic Soil Identification by CPTu
C. Champagne*, E. Peuse, R. Hryciw, E. Garcia

ISC2024.

Abstract
A soil behavior type (SBT) chart was developed to more reliably identify organic soil deposits at sites in the state of Michigan based on piezocone (CPTu) data. Organic soils are often highly compressible organic silts, clays, and peats. Many of these soils are fluvial with high void ratios and large compressibilities. These soils are typically removed prior to the construction of roadways and shallow bridge foundations due to the risk of excessive settlement. CPTu soundings were strategically performed alongside companion soil borings in which standard penetration testing (SPT) was performed and from which split-spoon and Shelby tube samples were recovered and tested. While many of the widely used SBT charts characterize the inorganic soils with reasonable agreement to the soil descriptions presented in the soil boring logs, the organic soils are often mischaracterized as inorganic clays. A hybrid SBT approach was therefore developed that yields more accurate characterization of the organic soils. The inorganic soils are reliably characterized by plotting the normalized tip resistance versus the normalized friction ratio. This SBT approach, however, ignores the valuable piezometric data provided by the CPTu. For organic soils, piezometric data helps to more reliably distinguish between inorganic clays and organic soils. As such, a screening tool was implemented to flag likely organic soils by plotting a parameter that accounts for both the tip resistance and pore pressure versus the normalized friction ratio before characterizing the likely-inorganic soils using existing approaches.
Abstract
A soil behavior type (SBT) chart was developed to more reliably identify organic soil deposits at sites in the state of Michigan based on piezocone (CPTu) data. Organic soils [...]
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Challenges in Site Characterization and Work Verification of Compacted Crushable Sands
P. Schober, J. Redgers, V. Bhushan*

ISC2024.

Abstract
During reclamation projects huge amounts of sands are dredged and placed to create artificial land. To increase the density and therefore to mitigate the potential risk of liquefaction as well as to increase the stiffness and internal friction angle of the sand, it is often necessary to compact the reclaimed sand. The performance targets for compaction are frequently verified by means of achieving a particular relative density that is generally correlated from Cone Penetration Tests (CPT). For many reclamation projects, due to the non-availability of local quartz or silica sands, crushable, carbonate or calcareous sands are used. In these crushable sands, due to the very high stress concertation below the CPT cone, the particles tend to crush. The well-known published correlations between the relative density and cone resistance are established for non-crushable silica sands and are thus not applicable to these crushable sands and can result in over treatment costing time and money. Usually, the crushing effect is quantified in a calibration chamber test and a project specific correction factor is introduced. Alternatively, to avoid this costly and time-consuming procedure the use of measuring the shear wave velocity with seismic CPTs (SCPT) is possible. The Cyclic Stress Ratio (CSR) for liquefaction analysis and other soil parameters required for the design verification can be correlated without being influenced by the crushing of particles due to the non-invasive procedure. This paper gives an overview of the common practice for work verification in crushable sand and shows an approach to determine the required compaction parameters using seismic CPTs.
Abstract
During reclamation projects huge amounts of sands are dredged and placed to create artificial land. To increase the density and therefore to mitigate the potential risk of [...]
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Experience of in situ geotechnical tests and their interpretation in organic soils and peat
M. Long*, G. Tucker, C. Thrane Leth

ISC2024.

Abstract
This paper reviews the use of piezocone (CPTU) testing to characterise and identify peats and organic soils. Examples of data for peat sites from several countries are given, including some experience of the use of T-bar and piezoball penetrometers in peat. These “full flow” devices show smoother resistance profiles than the equivalent from the CPTU and are perhaps representative of the peat mass with a reduced fibre effect. In CPTU tests, organic soils and peat are often characterised by low corrected cone resistance (qt) and high friction ratio (Rf). CPTU penetration in peat is often drained with data showing low pore water pressure coefficient (Bq) values. Rf broadly decreases with increasing degree of decomposition of the peat. However care needs to be taken in using Rf values in peat given the characteristically very low sleeve friction values (fs) encountered. It would seem that it is not always easy to distinguish between peat and underlying soft soils using CPTU alone. There may be some promise in inclusion of CPTU “add on” sensors particularly a seismic element to yield shear wave velocity (Vs). However there is some uncertainty in measuring Vs in peat both offshore and onshore so care is needed in this regard. Recently developed Soil Behaviour Type (SBT) charts from the Netherlands have also been trialled on several sites. This new formulation shows promise and warrants further study
Abstract
This paper reviews the use of piezocone (CPTU) testing to characterise and identify peats and organic soils. Examples of data for peat sites from several countries are given, [...]
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CPT based classification with focus on organic soils
A. Lengkeek*

ISC2024.

Abstract
Most published research on CPT based SBT classification is on mineral soils. Consequently, these classifications do not accurately capture the classification of soft organic clays and peats. Organic soft soils are frequently present within the Holocene deposits in the Netherlands and in other deltaic areas worldwide. Organic soils can be identified by a specific combination of CPT parameters such as a high friction ratio, low cone resistance and low pore pressure response. In contrast to other soft soils, the strength is not necessarily low. This paper presents an updated CPT based classification with focus on organic soils, for the non-normalized SBT chart (Robertson, 2010, Lengkeek et al, 2022) as well as a new classification based on the stress normalized SBT chart (Robertson, 2016). In the new proposed classifications, additional boundaries are set based on the CPT pore pressure measurements, as this appears to be successful to separate organic soils from mineral soils. The performance of the classifications can be quantified by metrics such as the F1 score. The F1 score of the new proposed classifications all show significant improvement.
Abstract
Most published research on CPT based SBT classification is on mineral soils. Consequently, these classifications do not accurately capture the classification of soft organic [...]
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Cone Penetration Response in Carbonate Sediments
S. Sharma*, C. Colreavy, N. Boylan

ISC2024.

Abstract
Cone penetration testing (CPT) is one of the most used site characterisation tools in geotechnical engineering. In offshore areas dominated by carbonate sediments, CPT is extensively used to characterise material types and assess their strength and flow characteristics. However, unlike for non-carbonate sediments where large number of empirical relationships are available correlating the CPT response with the corresponding soil behaviour and associated engineering parameters, there is still a lack of data correlating the CPT response with engineering behaviour of carbonate sediments. This paper presents CPT responses for different types of marine carbonate sediments. First, a brief background on carbonate sediments including key terminologies used and their characteristics in comparison to their non-carbonate counterparts are discussed. This is followed by examples of CPT data from major offshore project sites representing different type of materials ranging from uncemented fine grained (Muds and Silts) and coarse grained (Sand) sediments to variably cemented carbonate materials. The CPT results are then used, in combination with laboratory test data, to evaluate the suitability of standard soil behaviour type charts and indices available in the literature. Typical zone of results for carbonates sediments as a function of normalized cone parameters are also presented for reference purposes. Some challenges on the direct use CPT based methods to engineering analyses for carbonate sediments and the key areas of research from a practical engineering perspective are also briefly discussed.
Abstract
Cone penetration testing (CPT) is one of the most used site characterisation tools in geotechnical engineering. In offshore areas dominated by carbonate sediments, CPT is [...]
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Case studies for temporal variability In site characterisation
B. Look*

ISC2024.

Abstract
While site investigation data is typically focused on the spatial variability for site characterisation, those properties may change with time. Temporal variability needs to be considered in the design and construction of roads and high-level foundations. Seasonal variation occurs in the active zone and long-term changes occur 2 to 5 years after construction using expansive clay materials in adverse climate conditions. The latter may occur below the zone of seasonal variation. A case study for seasonal changes in subgrade strength at an uncovered test site when tested at 5 different times of the year. Measurement accounted for 30% of the variation, while temporal and spatial variation accounted for an additional 30% variation over the 1-year period of testing. An appropriate probability distribution function (PDF) is required for characteristic values. Constructing embankments to the equilibrium moisture content (EMC) is more important than the optimum moisture content (OMC), which is a short-term construction expedient. Time Domain Reflectometry (TDR) probes were used to monitor embankment moisture changes over a 4-year period for a new road construction on expansive clays. This included 1) an existing 30-year-old embankment during the project planning phase, 2) a trial embankment during design, and 3) the new constructed roadway embankments. All demonstrated the importance of understanding the EMC when expansive clays are being used for embankment construction. Results in other climatic environments are compared. The results show subgrade CBR tested at OMC is meaningless for such soils and in those extreme climates.
Abstract
While site investigation data is typically focused on the spatial variability for site characterisation, those properties may change with time. Temporal variability needs [...]
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Investigating crushing-induced particle shape change in granular material
S. Allaev, M. Kikumoto

ISC2024.

Abstract
High-pressure uniaxial compression tests were conducted under strain-controlled conditions using spherical glass beads. The study focused on investigating the compression behavior and particle fragmentation phenomena, particularly observing changes in particle size and shape resulting from fragmentation. The examination of particle shape, specifically sphericity and roundness, was emphasized. The samples comprised glass beads with uniform particle size and shape initially. It was observed that pressures exceeding 20MPa triggered particle fragmentation, leading to significant compression behavior. Notably, a softening phenomenon characterized by rapid fluctuations in compressive stress, despite a monotonic increase in strain, was observed during fragmentation. This phenomenon indicates the particles' catastrophic failure, unable to withstand the contact forces they previously sustained. Observations of particle shape revealed trends toward asymptotic distributions in cumulative curves for particle size, sphericity, and roundness. Moreover, changes in the cumulative curve of roundness were more pronounced compared to particle size and sphericity.
Abstract
High-pressure uniaxial compression tests were conducted under strain-controlled conditions using spherical glass beads. The study focused on investigating the compression [...]
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Piezoball and T-Bar Application on a Brazilian Soft Soil Deposit
J. Sosnoski*, A. Meier, G. Dienstmann, E. Odebrecht, H. Nierwinski, F. Mantaras

ISC2024.

Abstract
Research has already demonstrated advantages in performing piezoball tests when compared to piezocone in estimating the soil undrained shear strength (Su) along the stratigraphy and remolded strength (Sur) through cyclic tests, showing a shorter range of strength correction factors (N) and lower dependence on the soil stiffness index (Ir). Another possible application is estimating the remolded shear strength directly from penetration (qin) and extraction (qext) measurements without requiring cyclic tests. This research performed piezocone, vane, and piezoball tests (standard and cyclic) in a soft soil deposit in southern Brazil. Additionally, undisturbed samples were collected for characterization. The in situ investigation resulted in cone and ball factors in accordance with the international practice recommendation, resulting in similar profiles of undrained strength Su which increases with depth from 3 to 14 kPa and constant values of remolded undrained strength Sur. Regarding estimating the Sur through direct measurements of penetration and extraction of the piezoball, it was necessary to carefully evaluate the time laps between probe insertion and extraction to avoid overestimating the remolded strength.
Abstract
Research has already demonstrated advantages in performing piezoball tests when compared to piezocone in estimating the soil undrained shear strength (Su) along the stratigraphy [...]
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Geotechnical Characterization of an Earthfill Constructed from Schist Residual Soils
N. Cruz*, J. Cruz, F. Paiva, C. Rodrigues, A. Ferreira

ISC2024.

Abstract
Earthfills are anthropogenic soil massifs that were originated by different processes than those observed in traditional soil mechanics, thus revealing some deviations to the behaviour of common natural soils. The common characterization of earthfills is based in discontinuous testing such as nuclear densimeter gauge used together with laboratory compaction tests and the stiffness evaluation obtained from plate load tests, which does not give answers in the context of strength evaluation (Cruz et al. 2008; Cruz et al. 2006). The case study presented herein refers to the geotechnical characterization of an earth fill composed by evolutive materials obtained from the de-structuration of schists, which has developed excessive settlements. The performed geotechnical characterization consisted in boreholes and regular SPT tests, Dynamic Probing (DPSH), Piezocone (CPTu) and Marchetti Dilatometer (DMT) tests, as well as triaxial, shear box, consolidation and identification tests. DMT and CPTu tests were selected not only to obtain strength and stiffness parameters, but also because of its ability to access stratigraphy and unit weights. The whole set of obtained results are presented, compared and discussed, revealing a clear convergence between results as well as some interesting particularities that may be useful in fill characterization.
Abstract
Earthfills are anthropogenic soil massifs that were originated by different processes than those observed in traditional soil mechanics, thus revealing some deviations to [...]
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Observational Method of Evaluating Secondary Compression Settlement in Artificial Fills
D. Coduto*

ISC2024.

Abstract
Secondary compression can be an important source of settlement in artificial fills, even when these fills are well constructed. In some cases, especially when the fill thickness is greater than about 15 m, the resulting long-term settlements can adversely impact the performance of structures and infrastructure, and thus may necessitate special preventive design provisions. Yet, this source of settlement is often mistakenly overlooked. Secondary compression can be even more problematic when the fill is poorly constructed. Backfills of former open-pit mines are examples of practical projects where assessments of long-term secondary compression settlement are necessary, especially when these backfills are deep and/or not properly engineered. Laboratory assessments of secondary compression in these materials are inherently problematic and become impossible when the fill contains large particles or has other complicating characteristics. However, this problem is an excellent opportunity to apply the observational method where the coefficient of secondary compression, Cαε, is assessed in-situ using settlement monument data. This Cαε value is then used to forecast future settlements, which typically continue for decades, and thus provides essential information for the site-specific design of structures and infrastructure. However, the experimental and analytical processes for conducting these evaluations are more difficult than might be expected, and missteps can lead to significant errors in the computed future settlements. Some of these difficulties are due to limitations in our knowledge of the underlying physical processes and in the analytical models used to describe them. Methods of collecting the required field data and conducting these settlement evaluations are discussed based on experience with deep fills in California as well as published data from elsewhere.
Abstract
Secondary compression can be an important source of settlement in artificial fills, even when these fills are well constructed. In some cases, especially when the fill thickness [...]
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In situ and laboratory results of a bentonite-based block/pellet seal during saturation
A. Mesa-Alcantara*, E. Romero

ISC2024.

Abstract
The in situ Engineered Barrier (EB) experiment aimed at understanding the hydromechanical behaviour of sealing materials for high-level radioactive wastes as a combination of compacted blocks and high-density pellets made of Febex bentonite. The experimental program focused on the wetting process of a heterogeneous dual-component sample consisting of pellets and blocks with technological gaps. The homogenisation tendency was investigated by determining the final (local) dry densities and pore size distributions in both zones from post-mortem analyses. Global initial dry densities between 1.36–1.44 Mg/m3 were considered for the heterogeneous mixture, wetted at constant volume and constant vertical stress (oedometer conditions). The initially high-density zone of blocks with technological gaps expanded during hydration, reaching a lower dry density at saturation than the pellets’ zone. The initially low-density pellets’ zone with a high volume of inter-pellet pores underwent compression and reached a final high dry density on saturation. The experimental results were compared with the distribution of dry density at the in situ EB experiment after dismantling, and a good agreement between the laboratory and the in situ measurements was observed.
Abstract
The in situ Engineered Barrier (EB) experiment aimed at understanding the hydromechanical behaviour of sealing materials for high-level radioactive wastes as a combination [...]
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Evolution of fracture permeability in active clayey formations
A. Seiphoori*, P. Marschall, U. Mok

ISC2024.

Abstract
Opalinus Clay (OPA), a potential geological host formation for the disposal of high-level radioactive waste in Switzerland, is characterized by a low intrinsic permeability on the order of ~ 10-20 to 10-21 m2. Nonetheless, its effective permeability can increase significantly due to active fractures, which are influenced by factors such as fracture geometry, solid-liquid interaction, and stress conditions. The evolution of the permeability and geometry of such active fractures, particularly in rocks containing swelling clay minerals, is important for assessing the long-term safety of the repositories. Here we present the results of an experimental investigation focused on understanding the evolution of permeability in fractured OPA. We employed an advanced high-pressure triaxial system to evaluate gas permeability, followed by a phase where gas was replaced with synthetic water. We observed a three-order-of-magnitude reduction in apparent permeability as fractures evolved, primarily due to active clay minerals and the associated swelling deformations. Furthermore, we conducted a detailed analysis of the material's internal pore structure at each stage of the experiment using X-ray computed tomography. Results may be used to understand the underlying processes in the evolution of fracture permeability in clayey formations applied in hydrocarbon reservoirs, carbon sequestration, and nuclear waste containment.
Abstract
Opalinus Clay (OPA), a potential geological host formation for the disposal of high-level radioactive waste in Switzerland, is characterized by a low intrinsic permeability [...]
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On The Wildfire-Induced Changes In The Properties Of A Vegetated Clayey Slope Cover
N. Stasi*, V. Tagarelli, F. Cafaro, F. Cotecchia

ISC2024.

Abstract
Wildfires are generally believed to be detrimental to slope stability, by both damaging the vegetation and altering the hydro-mechanical properties of soil cover through burning action. However, the extent to which wildfires may impact on state of the vegetation and soil state is still an open issue, as it depends on several factors such as fire intensity, on the soil and vegetation state and type. The research activity was carried out with reference to in-situ test-site, the Pisciolo hillslope, where selected vegetation has been seeded and farmed, with the aim to assess its effectiveness in reducing surface water infiltration. The test site caught fire in September 2023, during which most of the vegetation was burned down. Pre and post fire soil properties were evaluated using laboratory and in-situ methods including Loss-on-Ignition (LOI), water drop penetration time (WDPT), and in-situ seepage tests (i.e., by means of Guelph permeameter and double ring infiltrometer). Furthermore, the wildfire-induced thermal stress in the soil was monitored with a thermocouple recording soil temperature within 15 cm b.g.l.. Monitoring results showed that significant wildfire-induced temperature variations were limited to the very near-surface soil layer, up to 25 cm; the soil organic matter decreased after the fire exposure; the hydraulic behaviour was also affected but only to a minor extent, since the coefficient of saturated permeability was found to change only slightly. The logged information may be used for a better understanding of the soil and vegetation post-fire evolution states. Indeed, this research activity is expected to impact the modelling of the slope-vegetation-atmosphere interaction at the ground surface, which is the factor mainly controlling the current activity of several weather-induced landslide in both fine and coarser slopes.
Abstract
Wildfires are generally believed to be detrimental to slope stability, by both damaging the vegetation and altering the hydro-mechanical properties of soil cover through burning [...]
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Influence of the Weathering Degree on the Dispersion Susceptibility of Allophanic Soils
A. Castañeda Jaimes*, J. Colmenares Montañez, L. Viveros Rosero

ISC2024.

Abstract
The behavior of allophanic soils is directly related to their fabric and structure. They are transformed according to their weathering degree through biogeochemical processes that may give rise to changes in the minerals. This paper investigated the influence of weathering degree on the susceptibility to dispersion in materials derived from volcanic ash soil in Armenia (Colombia). X-ray fluorescence (XRF) tests and scanning electron microscopy (SEM) tests were conducted to identify mineralogical composition and correlate it with the use of geochemical indices. Pinhole tests were developed on natural and compacted samples (with prior air and oven drying), to assess susceptibility to dispersion. It was found that the most weathered material exhibits lower susceptibility to internal erosion due to particle aggregation generated during the material alteration process. At similar dry density, natural materials present intermediate permeability values compared to compacted ones under both water content conditions. Samples dried in the air retain part of their structure and promote lower hydraulic conductivity values compared to samples dried in the oven, indicating that material alteration due to drying generates differences in porosity and hydraulic conductivity. The drying process at higher temperatures changes the material properties, eliminating the gel texture and hence the cementing bonds, inducing imminent changes in microporosity. The findings contribute to evaluating the application of allophanic soils for embankment construction, where the loss of cementation contributes to the degree of infiltration, reducing shear strength and affecting internal stability.
Abstract
The behavior of allophanic soils is directly related to their fabric and structure. They are transformed according to their weathering degree through biogeochemical processes [...]
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Collapsible Behaviour of a Compacted Lateritic Sandy Soil
I. Augusto Silveira*, B. Padovezi Rocha, H. Giacheti, R. Rodrigues

ISC2024.

Abstract
Collapsible unsaturated soils are characterized by a low-density composition and exhibit sudden settlement after wetting while maintaining in-situ stress levels. This issue is effectively mitigated by compaction, a simple and economical technique that improves the soil properties and geotechnical behaviour. In this study, the collapsible behaviour of a compacted sandy laterite soil is analysed, focusing on the influence of relative compaction, water content, initial suction and inundation stress. The primary aim is to analyse the effect of initial compaction conditions on collapse potential. Conventional and suction-controlled oedometer tests were conducted on soils from Ilha Solteira, São Paulo, Brazil, where there is a large amount of geotechnical data available. The laboratory data reveal that collapse deformations of compacted soil depend on relative compaction, initial water content, soil suction, and inundation stress. Poorly compacted soils exhibit greater susceptibility to collapse when wetted, and the magnitude of collapse potential varies with water content. Additionally, this study shows the influence of initial suction on collapsibility of less compacted soils. The laboratory results highlighted the importance of considering suction and inundation stress in understanding the collapsible behaviour of compacted soil, whereas traditional empirical methods often emphasize low density and water content as primary factors predisposing soils to collapse.
Abstract
Collapsible unsaturated soils are characterized by a low-density composition and exhibit sudden settlement after wetting while maintaining in-situ stress levels. This issue [...]
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Measurement of soil temperature with depth using multiple sensor arrays
M. Zizzi*, G. Elia, O. Bottiglieri, F. Cotecchia

ISC2024.

Abstract
Accurate measurement of soil temperature is essential for the diagnosis of various environmental processes and their impact on ecosystems. Indeed, continuous monitoring of temperature profiles with depth provides valuable understanding of the soil thermal response, which could support studies related to climate change, hydrology, agriculture, and geothermal energy. The paper describes an innovative installation procedure of temperature strings (CS225) to measure the temperature field of an undisturbed soil deposit at different depths in real time. The strings consisted of multiple temperature probes connected in series, placed at specific depths within the soil profile. The CS225 probes require little maintenance and no initial calibration, guaranteeing a high accuracy and resolution of the temperature measurements. The initial field measurements have shown a good performance of the probes, which have been able to detect the gradual decrease of soil temperature and the reduction of oscillations with depth. Further research will include the detailed analysis of the influence of ambient wind speed, solar radiation and soil moisture on the heat transfer from the ground surface to the deeper soil layers, as well as laboratory tests and numerical analysis.
Abstract
Accurate measurement of soil temperature is essential for the diagnosis of various environmental processes and their impact on ecosystems. Indeed, continuous monitoring of [...]
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Monitoring Climate Induced Degradation Processes of Dutch Regional Dykes
I. de Wolf*, C. Jommi

ISC2024.

Abstract
A large part of the Dutch regional dyke network is classified as drought-susceptible given that both the dyke body and the foundation layers consist of soft organic soils. The erratic weather conditions over recent years, which included prolonged drought, new temperature records and intensified rainfall, are linked to an increased number of accidents related to dyke degradation. As global warming continues to exacerbate extreme weather, there is a growing concern on the impact of changing climatic conditions on this type of regional dykes. Poor understanding of climate induced soil degradation processes poses a serious challenge in the development of adaptation strategies. The challenges are caused by the large variety of interplaying factors, dynamic environmental actions and the complex description of coupled degradation processes with varying spatial-temporal scales. This study demonstrates the potential use of field monitoring to overcome some of these limitations. Field monitoring data on ten Dutch regional dyke sections, with varying geometry, stratigraphy and vegetation are presented. The data provide insight into changes in dyke hydraulic state as a function of atmospheric conditions and allow to infer possible climate induced soil physical degradation mechanisms depending on dyke characteristics. To fully evaluate the impact of degradation on the water protection system, ancillary monitoring data are required, able to quantify the mechanical implications of climate induced state variations. The design of dedicated monitoring set up on three selected dykes, which will serve as representative case studies for the development of geotechnical assessment methods, is eventually presented.
Abstract
A large part of the Dutch regional dyke network is classified as drought-susceptible given that both the dyke body and the foundation layers consist of soft organic soils. [...]
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Multi-Sensor Core Logging of Marine Sediments for Continuous Thermal Conductivity Profiles
S. Smith*, M. Vanneste, T. Faleide, A. Bertrand

ISC2024.

Abstract
Thermal conductivity of shallow (
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Characterization of Thermal Conductivity of Backfill Materials for UPCS by Various Methods: Lab, in Situ and Numerical Analysis
B. Dinh, Y. Kim*, C. Nguyen, G. Kang

ISC2024.

Abstract
This research evaluates the thermal properties of the proposed backfill materials (prepacked concrete (PAC)) that function as the heat release medium for the underground power cable system (UPCS). First, a hot disk sensor was used to measure the thermal conductivity of small-scale backfill materials in the laboratory. The horizontal thermal response test (TRT) was then performed with a 5 × 3 × 2 m full-scale sample for the in-situ evaluation. Afterward, the data from the TRT was utilized to couple with the infinite line source model (ILS) to predict the thermal conductivity of the full-scale sample. Finally, the thermal conductivity of the PAC was back-calculated using COMSOL Multiphysics. All these tests were also performed with natural sand (conventional backfill material) to compare with the PAC. Thermal conductivities calculated by numerical simulation and the ILS model were in good agreement (difference < 3%), demonstrating that the proposed ILS model coupled with horizontal TRT data is appropriate for estimating the thermal conductivity of full-scale backfill material in situ. The results of three testing methods indicated that the prepacked concrete has a high thermal conductivity (> 2 W/(mK)), thus satisfying the heat release ability requirement for the UPCS. The laboratory test slightly underestimated the thermal conductivity (less than 8%) compared to the estimated values from the ILS model and numerical model involving prepacked concretes; however, natural sand showed a significant difference (1.365 W/(mK) and 1.8 W/(mK), 32 %) attributed to the influence of the water content change during the TRT. Therefore, it is recommended that the in-situ testing conditions should be considered for the sand (or soils) to avoid the overestimation or underestimation of their thermal conductivity.
Abstract
This research evaluates the thermal properties of the proposed backfill materials (prepacked concrete (PAC)) that function as the heat release medium for the underground power [...]
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Interpreting repeated CPT in unsaturated soils
C. Jommi*, S. Muraro, C. Chao

ISC2024.

Abstract
Cone penetration tests, CPTs, are extensively used in the Netherlands to assess the stability of fourteen thousand kilometres of dykes protecting the country from flooding. On the regional dykes, site testing is planned and executed only from spring to autumn. The data collected in the drier season of the year must be used then in safety factor calculation for dyke stability with reference to the worst expected conditions, including the highest weights and the highest water pressures over the year. Inferring reliable values of the shear strength in a different season implies understanding the unsaturated response of the dyke material and the effect of variable water content on the CPT response. In previous studies referring to CPTs in unsaturated soils, it was observed that both the cone resistance and the sleeve friction depend on suction, however, only the cone resistance was used to determine the shear strength in combination with water content or suction probes installed into the ground. In this contribution, we analyse an extensive set of data, coming from repeated CPTs performed over one year on the Maasdijk near Oijen in the Netherlands. The data are elaborated to investigate whether the entire set of data can be exploited to try to derive the water content and the constant water content shear strength at the same time, if the test is repeated in different seasons.
Abstract
Cone penetration tests, CPTs, are extensively used in the Netherlands to assess the stability of fourteen thousand kilometres of dykes protecting the country from flooding. [...]
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Estimation of Pore Pressure for Unsaturated-Saturated Bentonite Sand Mixture
T. Nishimura*

ISC2024.

Abstract
To investigate thermal hydration mechanical chemical couple phenomena is an important issue of the high-level radioactive waste disposal and a key indicator of artificial barrier system. Major objectives of the thermal and mechanical site characterization include the status of the environmental. Several research reports are aimed at the barrier layers for heating from radioactive waste disposal. This study appears the occurrence of the pore pressure under heat conditions for bentonite and bentonite-sand mixture material, which are completely undrained condition and unexhausted condition. It is considered that mechanics of pore pressure in macro-micro void structure due to heating-cooling repetition. A thermal chamber is used in heating method, which have high specification with accurate controlling sensitivity. The maximum temperature is 80 degrees Celsius temperatures. The prepared specimens are unsaturated specimens and saturated specimens, and silica sand are mixture into three different bentonites that various dry densities are required. Two different solutions are prepared for saturated specimen, which are distilled water and salinity water with concentration of 3.5 %. The specimens are placed into a thermostat oven, and heating application is applied isotropic conductivity. The obtained results are significant as followings; The measured pore pressures are obviously with increment of temperature, and the sand mixture ratio is small influence factor. Also, large por fluid pressures are produced for saturated condition that indication of small pore fluid pressure is verified for unsaturated specimen comparison with saturated specimen.
Abstract
To investigate thermal hydration mechanical chemical couple phenomena is an important issue of the high-level radioactive waste disposal and a key indicator of artificial [...]
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In Situ Measurement of Soil Thermal Properties: a New Prototype
A. Garcia-Fontanet*

ISC2024.

Abstract
As part of the THERMALTUNNEL R&D, partially funded by Centro para el Desarrollo Tecnológico e Industrial (CDTI), a Spanish Ministry of Science and Innovation agency, PRO GEO has developed a soil penetration prototype that measures soil temperature and the thermal properties of the ground (thermal conductivity and specific heat) at different depths. The prototype is the size of a conventional CPT and contains an internal heat source with local thermocouples. A data acquisition system measures the temperature both in the prototype itself and in the surrounding ground through a penetration needle protruding from the main body of the prototype. The thermal parameters are determined by analyzing the measured heating and cooling temperature curves using the finite element codes CODE_BRIGHT (Olivella et al., 1993) and G-PFEM (Monforte, 2018). In this later numerical code, a thermal analysis module has been incorporated within the framework of the project. The operation of the prototype has been satisfactory in laboratory tests through a calibration chamber setup with granular soil under different controlled conditions of water saturation and porosity to assess the impact of those variables on the obtained values of soil thermal conductivity and specific heat. The back-analyzed parameters from the calibration chamber results have been compared with point tests (thermal conductivity and specific heat tests). The project has been developed with the cooperation of CIMNE – International Centre for Numerical Methods in Engineering.
Abstract
As part of the THERMALTUNNEL R&D, partially funded by Centro para el Desarrollo Tecnológico e Industrial (CDTI), a Spanish Ministry of Science and Innovation agency, PRO [...]
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Geotechnical investigation of a fissured highly expansive clay profile
R. Murison, T. Gaspar, S. Jacobsz, G. Heymann, Y. Narainsamy

ISC2024.

Abstract
This study details some observations and challenges in interpreting site investigation data for highly expansive soils. Expansive soils exhibit large volume changes in response to changes in water content. This leads to a high degree of reworking and often a strongly fissured macrofabric in situ. A site underlain by a ~7.0 m thick active clay deposit, containing highly plastic and highly expansive smectites, was chosen for large-scale pile tests. Two identical areas were identified for the tests. The first was kept at natural water content conditions. The other was kept submerged under water through infiltration wells for six months, aiming to facilitate maximum swell of the active layers. As part of the site investigation, continuous surface wave (CSW) tests and standard penetration tests (SPT) were conducted at various points in time. These results have been compared for the natural water content and the submerged profiles. Small-strain moduli interpreted from the CSW tests showed no significant difference between the two profiles, contrary to the intuitive expectation that inundation of the highly expansive clay layers and dissipation of suctions in the order of several megapascals might significantly reduce the stiffness. Due to the small strains imposed during the test, the characteristics of the fissures and joint infill material are measured, rather than that of the intact masses. The large-strain SPT results showed a softer response for the inundated profile, as expected. Challenges in obtaining intact tube samples from the stiff and highly fissured unsaturated profile have also been discussed.
Abstract
This study details some observations and challenges in interpreting site investigation data for highly expansive soils. Expansive soils exhibit large volume changes in response [...]
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Characteristics of the Electroresistivity of a compacted Iron Ore Tailing
F. Marinho, B. Dos Santos, J. Da Silva*, B. Delgado, M. Hora

ISC2024.

Abstract
The new legislation in Brazil has brought more attention to the technique of stacking filtered iron ore tailings for mining waste disposal. To minimize the risk of liquefaction, it's important to maintain the compacted structure in an unsaturated condition. This requires knowledge of the hydraulic characteristics of the material in order to evaluate the long-term performance of the embankment and design an adequate monitoring system. One way to track the material's behavior in the field is through electrical resistivity techniques. Using an electrical resistivity measurement system at various frequencies and current levels, we evaluated the behaviour of compacted iron ore waste. The examined tailings have been deposited in filtered tailings piles, which are intended to exceed a height of 100 meters. This study aims to investigate the electrical response of the material to different levels of water content, degree of saturation and suction. It was possible to establish good correlations between electrical resistivity and factors such as suction, degree of saturation, and water content. It was also identified an association between the electrical resistivity and the optimum water content
Abstract
The new legislation in Brazil has brought more attention to the technique of stacking filtered iron ore tailings for mining waste disposal. To minimize the risk of liquefaction, [...]
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In Situ Test Methods for Thermal Site Characterisation – A Comparison
L. Vrielink*, J. Peuchen, N. Parasie

ISC2024.

Abstract
The demand for thermal site characterization has risen noticeably in the past decade, particularly for design of geothermal energy solutions and for design of in-ground power cable networks. The results of thermal characterization of a site are typically incorporated in a ground model based on environmental, geological, geophysical and geotechnical geodata. This paper compares in-situ test methods for thermal site characterization of soil. The comparison considers method applicability, deployment method, maximum test depth, test duration and uncertainty of results. A distinction is made between three categories of in-situ tests: (1) in-situ tests using active heat generation, (2) in-situ tests using passive heat generation and (3) in-situ tests with no specific thermal data acquisition
Abstract
The demand for thermal site characterization has risen noticeably in the past decade, particularly for design of geothermal energy solutions and for design of in-ground power [...]
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Use of geosynthetics to close a contaminated area in a metallurgical industry in the state of bahia
T. Andrade, I. Silva, L. Rezende, D. Eloi*, M. Neto

ISC2024.

Abstract
The study for closure and monitored natural attenuation/stabilization of industrial waste deposits plays a fundamental role in the process of groundwater quality management, providing information for understanding the contaminants evolution and enabling decision-making, with the purpose of isolating waste, contaminant concentrations, toxicity and mass and/or volume reduction to levels adequate to protect human health and the environment, within a reasonable period of time. The aim of this study was to propose an environmental remediation solution for a contaminated material disposal area using the case study of a metallurgical industry located in Bahia, Brazil. To this purpose, four conditions were provided for compliance: i) control of dust, odor and erosion, ii) control of contaminant release, iii) chemical stabilization of waste and iv) soil recovery. Based on the results obtained in environmental investigation studies and information from the area, the best solution in an attempt to naturally stabilize the area would be the use of geosynthetics as a physical barrier between the contaminated material disposed in the area and the rainwater. In this way, infiltration of rainwater into the landfill and the migration of percolated liquid with risk of contamination to the soil, groundwater table and surface water bodies is avoided. It is still possible to monitor the effectiveness of the proposed solution with the installation of instrumentation such as water level indicators and piezometers.
Abstract
The study for closure and monitored natural attenuation/stabilization of industrial waste deposits plays a fundamental role in the process of groundwater quality management, [...]
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Interpretation of CPTu data using machine learning techniques to develop the ground model of a dam
M. Sottile*, J. Crocker, L. Roldan

ISC2024.

Abstract
Building a ground model through manual processes can be time consuming, as large amounts of data need to be classified to define the extent and spatial distribution of the different soil materials. This paper delves into the application of machine learning (ML) methodologies, in conjunction with in-situ geotechnical testing data, to develop the ground model for a downstream dam founded on both weak and liquefiable soils. The dam covers a linear extent of approximately 800 m and was extensively characterized by means of in-situ tests, including 206 cone penetration tests (CPTu), 37 boreholes and 35 test pits. The performance of two unsupervised ML clustering algorithms are compared: Density-Based Spatial Clustering of Applications with Noise (DBSCAN) and an extended version with a hierarchical component (HDBSCAN). The clustering uses CPTu data, which consists of the normalized cone tip resistance (Qtn) and the normalized sleeve friction (Fr) varying with elevation. Nearby borehole logs are used to evaluate the results of both clustering methods for a single single CPTu sounding using different clustering parameters. Then, a global clustering including several CPTu soundings is done and results are compared with the ground model that was manually made using Leapfrog software. Both methods show very good performance, with HDBSCAN being better and more robust.
Abstract
Building a ground model through manual processes can be time consuming, as large amounts of data need to be classified to define the extent and spatial distribution of the [...]
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Cyclic Cone Penetrometer Tests: Worthwhile?
C. O'Loughlin*, F. Bransby, S. Mani, B. Bienen, P. Esfeh

ISC2024.

Abstract
This paper explores the merit of including cyclic episodes in cone penetrometer tests to measure changes in sleeve resistance during cycling. Tests were carried out in a geotechnical centrifuge in a kaolin clay and a dense silica sand. The data from the tests in clay indicate that the cone sleeve mobilises the remoulded undrained shear strength during the initial penetration, but that with continued cycling, the mobilised interface shear strength reduces to around one-third of the remoulded undrained shear strength before increasing. The initial reduction is considered to be due to local consolidation around the cone sleeve (leading to total stress reduction), whereas the subsequent increase is attributed to consolidation- induced strength hardening. Tests in sand also indicate a reduction in sleeve friction during cycling, consistent with the shear band contraction mechanism associated with friction fatigue of piles in sand, but with no consolidation-induced hardening behaviour as these tests were drained. The findings suggest that cyclic cone penetrometer tests may be a convenient means of gathering data for geotechnical design for problems where the cyclic response at the clay/structure interface is of interest. Considerations on the implications for offshore site investigations are provided.
Abstract
This paper explores the merit of including cyclic episodes in cone penetrometer tests to measure changes in sleeve resistance during cycling. Tests were carried out in a geotechnical [...]
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Geotechnical Characterization of Dredged Material from Rio Grande’s Port, Brazil
I. Soares Ribeiro*, H. Nierwinski, D. Freitas Fagundes, R. Pinheiro Maria

ISC2024.

Abstract
Dredging works are essential to ensure navigability in Harbors and waterways. However, this crucial activity generates millions of tonnes of waste each year worldwide. Since the disposal of dredged material is responsible for several environmental impacts, entrepreneurs and engineers must find creative uses for it. Therefore, this study aims to characterize a local dredged material to assess its properties and suitability for geotechnical applications. With this knowledge, this paper presents a series of experimental tests on dredged material samples retrieved from Rio Grande's Port, Brazil. The experimental program includes determining Atterberg limits, sieve and sedimentation analysis, pH and SEM analysis, compaction curve, and unconfined compressive strength in a reconstituted state. The results showed that the material is sandy lean clay, with unfavourable strength characteristics for geotechnical work in a raw state. However, with the advent of chemical stabilization techniques, there is potential for enhancing its suitability for geotechnical applications. By exploring methods such as adding binders like lime or Portland cement, the material's strength and stability could be significantly improved, opening up possibilities for its utilization in various engineering projects. This study contributes valuable insights into the potential reclamation and beneficial reuse of dredged material, ultimately aiding in the sustainable management of harbor and waterway dredging operations
Abstract
Dredging works are essential to ensure navigability in Harbors and waterways. However, this crucial activity generates millions of tonnes of waste each year worldwide. Since [...]
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When Did Geotechnical Data Become A Point Of View: A Case Of Numerical Analysis Vs Site Data
B. Look*

ISC2024.

Abstract
The construction of a permanent bridge required a temporary bridge parallel to the permanent bridge alignment. Preloading of the permanent bridge abutment occurred under a separate early earthworks contract. That fill was removed, and the temporary structure was constructed. The fill was then replaced behind the abutment. Movement of the southern abutment of the permanent bridge was identified but with a gap of several weeks in survey monitoring due to a XMAS break period. The abutment had moved towards the river and temporary bridge. Potential causes for movement were investigated by additional investigation adjacent to and far away from the temporary bridge piles. Post movement tests carried out included: Dilatometer Testing (DMT) to assess for shear zones (if any) for slope instability, Cone Penetration Testing (CPTu) to assess strength changes (if any) to proximity of piles and new inclinometer readings. INSAR data was also obtained. A 3-D finite element analysis (FEA) carried out by a consultant matched the measured lateral displacements at the adjacent bridge. Based on that correlation, it was concluded that the removal of the close-ended temporary piles was the main cause of the excessive movement, and this initiated a contractual claim. Correlation is not causation. This case study provides a background on the site data and numerical analysis. The FEA did not include much of the site observational and site data post movement. Given the FEA was given the same credence as the site data, this suggests that data is now considered a point of view.
Abstract
The construction of a permanent bridge required a temporary bridge parallel to the permanent bridge alignment. Preloading of the permanent bridge abutment occurred under a [...]
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A CT-based approach to assess sample quality in soft soils
J. Pineda*, N. Sau, K. Ouyang, M. Arroyo

ISC2024.

Abstract
The paper discusses the performance of a novel tool based on computed tomography (CT) to evaluate sample quality in soft soils. This new technique is applied to the low-plasticity Mediterranean deltaic deposits found in the region of Castello d’Empuries at the Costa Brava, in Catalonia (Spain). Tube specimens of variable diameters retrieved using open samplers (Shelby) as well as Osterberg-type fixed-piston samplers were scanned in this study. Statistical analysis of the CT images allows to define a quantitative index of sample quality. Sample quality classification based on this new non-destructive CT-based measure compares well with quality classification based on the well-established recompression sample quality index, e/e0.
Abstract
The paper discusses the performance of a novel tool based on computed tomography (CT) to evaluate sample quality in soft soils. This new technique is applied to the low-plasticity [...]
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Paired in situ tests for site characterization and geotechnical design optimization
D. Berisavljević*, N. Božović, N. Stanić

ISC2024.

Abstract
The paper shows recent experience in performing and interpreting the three most common in situ tests for site characterization: cone penetration test (CPT), seismic dilatometer test (SDMT) and Menard pressuremeter Test (MPT). It is shown that an adequate selection of in situ test methods for site characterization can be used to correctly predict the pile head load-settlement curve. Menard pressuremeter design rules, which were established in the 1st and a draft version of the 2nd generation of Eurocodes, can be applied to SDMT readings to obtain the pile bearing capacity. It was found that corrected lift-off pressure p0 obtained in the SDMT test is similar to the Menard limit pressure pl in clay, while pressure p1 (SDMT) is similar to pl in sand. All results used in the analysis are obtained on a large-scale project where investigations are strictly controlled and performed in accordance with Eurocode standards.
Abstract
The paper shows recent experience in performing and interpreting the three most common in situ tests for site characterization: cone penetration test (CPT), seismic dilatometer [...]
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On the Effectiveness of MOSTAP Sampling in Tailings
P. Oelofse*

ISC2024.

Abstract
The MOSTAP sampling apparatus is a popular tool in geotechnical investigation, since MOSTAP sampling can be done efficiently and cost effectively with the same rig used for CPT testing. Although few publications exist discussing the nuances and application of the MOSTAP sampler in practice, it is generally found that the MOSTAP sampler provides lower quality undisturbed samples when compared to piston tube or block samples. This paper discusses the experiences and learnings from geotechnical investigations where the MOSTAP sampler was employed in platinum and discard sand tailings in Southern Africa. A comparison between different sampler diameters at the same site showed significant improvements in sample recovery with larger diameter samplers. Ancillary equipment such as a core catcher and nylon stockings have significant effects on sample recovery and quality. The soil type and degree of saturation of samples also have a significant effect on sample recovery and sample quality. Transportation and storage of samples were identified as major contributors in moisture loss and sample disturbance. Even with the potential challenges in obtaining a representative sample at depth, MOSTAP samples are shown to be greatly beneficial in evaluating a soil profile and density determination with high confidence, especially when paired with index tests. The opportunity is identified where diligent sample measurement and tracking can provide reliable and invaluable information about a relevant soil stratum. Advanced laboratory testing (e.g., triaxial and oedometer tests) is not recommended on undisturbed MOSTAP samples, these should rather be remolded for critical state line testing, if relevant.
Abstract
The MOSTAP sampling apparatus is a popular tool in geotechnical investigation, since MOSTAP sampling can be done efficiently and cost effectively with the same rig used for [...]
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Combining penetration resistance and shear-wave velocity to quantify soil microstructure for liquefaction assessment
R. Andrus*

ISC2024.

Abstract
This paper discusses two ratios involving penetration resistance and shear-wave velocity (VS) that have been proposed for quantifying the influence of microstructure in aged and cemented soils for liquefaction assessment. The first ratio is the small-strain shear modulus (Gmax) divided by the cone penetration test tip resistance (qc). Because Gmax/qc is dimensionless, it can be expressed as a ratio of measured VS divided by a function of qc with velocity units. The second ratio is the measured VS divided by an estimated VS from penetration resistance-VS relationships for relatively young sand deposits (MEVR). The advantages and limitations of both ratios are discussed. The influence of various fines content (ð¹ð¹ð¹ð¹) corrections on ðððð, penetration resistance-ðððð relationships, and a relationship between MEVR and the liquefaction cyclic resistance ratio correction factor for microstructure (ð¾ð¾ð·ð·ð·ð·) is evaluated using two published datasets. The results show the ð¹ ð¹ð¹ð¹ correction to ðððð is minimal in the range for which the correction was derived. The ð¹ð¹ð¹ð¹ corrections to qc and standard penetration test blow count are significant for silty soils, having a net effect of lowering the penetration resistance-ðððð relationships and increasing the slope of the ðððððððð-ð¾ð¾ð·ð·ð·ð· predictive relationship
Abstract
This paper discusses two ratios involving penetration resistance and shear-wave velocity (VS) that have been proposed for quantifying the influence of microstructure in aged [...]
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Site characterization of large hydropower projects
T. Trick*, K. Kontar, G. Klee, M. Stolz

ISC2024.

Abstract
Hydropower plays an important role in the context of the energy transition contributing to the reduction of the CO2 emission through a permanent power production as run-of-river scheme as well as for energy storage as pump-storagescheme. Nowadays large hydropower plant designs comprise tunnel, cavern and shaft excavation work known as head race and pressure tunnel or pressure shaft. The powerhouse is often placed within a large underground cavern. The results of a ground investigation phase including the determination of in-situ parameters derived from tests in boreholes drilled from the surface are crucial for a preliminary design of the hydropower plant. Additional in-situ measurements are frequently carried out within an exploratory tunnel to confirm the first predictions and to characterize in detail the mechanical and hydraulic properties of the rock mass. Solexperts portfolio of in-situ well tests comprise the assessment of hydraulic properties vs. depth through hydraulic testing of isolated borehole sections along the borehole axes, the determination of geomechanical parameters like deformation- and Young’s modules through borehole dilatometer tests and rock stress measurements conducting hydraulic mini-frac tests. Plate load tests which use surficial loading are performed in small tunnels or test adits to measure the deformation characteristics of a rock mass on a larger scale.
Abstract
Hydropower plays an important role in the context of the energy transition contributing to the reduction of the CO2 emission through a permanent power production as run-of-river [...]
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Ground Model Workflow with DAARWIN
I. Jaqués, C. Cano, J. Llopart*, B. Solà, I. Aliguer

ISC2024.

Abstract
Structural geological models are used to understand and visualize how geological materials are organized below the Earth surface. This technique is crucial in different fields of geomechanics such as mining to identify mineral deposits and to plan mining operations, environmental engineering to assess the contamination of soil and groundwater and to design remediation strategies, and civil engineering to design foundations, tunnels and other underground structures. In this sense, ground models allow the engineer to understand and to visualize the spatial organization of subsurface geological structures and, additionally, it is possible to evaluate the spatial distribution of material properties which is essential in any geomechanical study prior to any project. In this context, SAALG Geomechanics through DAARWIN web platform provides a suitable software tool for the geotechnical engineer to perform the complete ground model workflow. The process starts introducing borehole data from different sources and then, the engineer can visualize and interpret borehole logs, define geomechanical units and assign parameters from in-situ and laboratory tests, as well as assign units’ geometry from geological layers. Finally, the user can feed this information to the system to obtain a 2D cross-section, that can be exported to the commercial Finite Element software PLAXIS and use this PLAXIS model for geotechnical design and more advanced analyses such as Sensitivity analysis and Back-Analysis, which are also implemented in DAARWIN.
Abstract
Structural geological models are used to understand and visualize how geological materials are organized below the Earth surface. This technique is crucial in different fields [...]
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Combined resistivity and seismic measurements along linearly extended earth structures - acquisition and interpretation approaches
C. Comina*

ISC2024.

Abstract
Geotechnical parameters of linearly extended earth structures, such as embankments and earth dams, are usually obtained from localized investigations through drilling or penetration tests, commonly time and cost consuming. Non-invasive geophysical investigations may be considered an alternative approach for the geotechnical characterization of these structures, given their surveying speed and their depth and length of investigation. Particularly, new acquisition approaches with the use of appropriate streamer cables could strongly reduce the acquisition times making geophysical surveys ideal for a preliminary screening of these structures. Specifically, resistivity and seismic methods can be adopted given that these two methodologies could offer complementary information with respect to the pore fluid properties (resistivity methods) and the solid skeleton characteristics (seismic methods). Also, through specific correlations, relevant geotechnical parameters for the evaluation of the stability of these structure and its efficiency (i.e. hydraulic conductivity, porosity and others) can be obtained. In this paper a review of the methodologies developed in recent years for data acquisition along linearly extended earth structures is reported with special focus on the use of combined electric and seismic streamer cables. Suggestions with respect to interpretation approaches and data elaboration are also analysed.
Abstract
Geotechnical parameters of linearly extended earth structures, such as embankments and earth dams, are usually obtained from localized investigations through drilling or penetration [...]
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Long-Term ERT Monitoring Data Analysis to Set Slope Instability Attention Thresholds Based on Water Level Fluctuations
R. Bianchi*, F. Brambilla, A. Hojat, G. Tresoldi, L. Zanzi

ISC2024.

Abstract
In this paper, we discuss the results of long-term electrical resistivity tomography (ERT) monitoring of a critical slope located on an important high-speed railway gallery. Data were acquired by a customized ERT system from 24 March 2022 until 31 august 2023 and were analysed with the final objective of defining thresholds of attention for resistivity changes derived from water table fluctuations after heavy rainfalls. This helps the authorities in reducing the hydrogeological risk impacts related to potential slope instabilities triggered by extreme meteorological conditions. In order to continuously observe water level changes, five piezometers were also integrated with the ERT monitoring system which is also accompanied by a meteorological station. All datasets were inverted using a time-lapse algorithm that was optimized to minimize artifacts generated by the subsurface complex geology of the site. Due to the long period considered, seasonal temperature corrections on resistivity values were also explored by calibrating a seasonal model of soil temperature versus depth and evaluating the corresponding effects on the resistivity tomographic maps. Finally, the correlation between resistivity values and piezometric levels was studied by producing scatterplot graphs for a selected subzone of the ERT sections. Based on this analysis, a preliminary threshold of attention was defined.
Abstract
In this paper, we discuss the results of long-term electrical resistivity tomography (ERT) monitoring of a critical slope located on an important high-speed railway gallery. [...]
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Early Screening for Improved Management of Geo-risks
R. Eddies*, R. Wood, M. Staring

ISC2024.

Abstract
Across several sectors including medicine and agriculture and the extractive industries, availability of early information from screening delivers disproportionate downstream benefit to key stakeholders. With the aim of reducing uncertainty to manage geo-risks in the subsurface, site characterisation for geotechnical engineering is mainly executed following a project owner’s final investment decision (FID) and continues to rely predominantly on conventional investigation techniques that inform both the geotechnical design and construction phases of infrastructure development. However, historical project performance of capital works developments tells us that geo-risks continue to play a role in unwanted engineering business outcomes in the form of schedule and cost overrun associated with earlier cost underestimation. Fundamentally, we recognise that the construction sector would benefit from earlier, faster, and better representation of the subsurface in the top 50 m to 100 m using techniques with a light footprint and low permitting requirements at the earliest stages of project development. We describe an example early-phase screening solution based on adapted ambient noise tomography. Screening at feasibility and planning phases can help to mitigate the impact of human bias arising from epistemic uncertainty in the subsurface and can improve early decision-making where the opportunity to influence project outcome is greatest and at lowest cost. Screening coupled with an optimised conventional intrusive investigation during the execution phase can complete the information set for full project design at considerably reduced levels of subsurface uncertainty leading to improved engineering business outcomes. The industry is encouraged to promptly incorporate the screening philosophy into feasibility and planning activities and into design codes for geotechnical design and construction.
Abstract
Across several sectors including medicine and agriculture and the extractive industries, availability of early information from screening delivers disproportionate downstream [...]
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Interpretation of geotechnical data from an upstream dam for preparation of the site response analysis
W. Durval Soares de Carvalho, T. Andrade, R. Viola, J. Ccotohuanca, M. Neto, D. Eloi*

ISC2024.

Abstract
Despite seismic studies in Brazil not being common in the engineering practice as Brazil is a tectonically stable continental region, recent Brazilian regulations require seismic evaluation as supporting studies for decommission and decharacterization projects. Although there exist some critical issues such as limited laboratory data because of sampler processes related to the upstream raised tailings dams, standard tailings and soil foundation characterization, in addition to the field investigation including piezocone (CPTu), seismic piezocone (S-CPTu) and geophysical surveys are the main sources for supporting the characterization of the dynamic properties of the geostructures. This paper presents a brief discussion about the main aspects concerning to the site response analysis carried out for an upstream raised tailings dam (case study), located in Minas Gerais, Brazil. Frequency domain 1-D amplification analyses were conducted by relating local-like representative seismic records and dynamic natural characteristics of the soil profiles to evaluate the seismic response of the case study. Results showed that the maximum accelerations along the profiles are greatly influenced by the presence of the soft foundation tailings layers, and the level of amplification or attenuation is strongly influenced by the tailings layer thickness as well as the frequency content of the applied ground motions. The study pointed out that the site-specific response can support the definition of the appropriate seismic parameters to be used in engineering projects in Brazil.
Abstract
Despite seismic studies in Brazil not being common in the engineering practice as Brazil is a tectonically stable continental region, recent Brazilian regulations require [...]
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New processing methodology of televiewer data for the definition of geotechnical and structural domains
M. Heredia Bilbao*, R. Sánchez Marín, R. Cano Martín, A. Deu Lozano, P. Martínez Diaz

ISC2024.

Abstract
Six structural domains were defined using data from acoustic televiewers and oriented boreholes as part of the reopening of the old Aznalcóllar mining site in Sevilla, southern Spain, by Minera Los Frailes (MLF). Additionally, geotechnical subdomains were defined within each structural domain, classifying the subdomains based on geotechnical parameters obtained from the geotechnical logging of boreholes and through correlations. The methodology used to define the domains allows mine design and planning to be done with enough accuracy to determine the underground excavation needs and the systematic methodology. The main source of this new structural information was acoustic borehole image televiewers (ABI) and, on a much minor scale and as a complement for ABI data, oriented boreholes. This paper describes the methodology used for this definition, some of the challenges encountered during the investigation, the main results obtained and the utility of these defined structural domains in the development of the MLF mining site reopening. Additionally, a preliminary approach to an updated methodology in the definition of structural domains with the combination of televiewer data, both acoustic and optical, with data obtained from other downhole probes is also included.
Abstract
Six structural domains were defined using data from acoustic televiewers and oriented boreholes as part of the reopening of the old Aznalcóllar mining site in Sevilla, southern [...]
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Multi-Method Geophysical Assessment of a Shallow Complex Landslide
M. Rahimi, C. Wood*, S. Rahimi

ISC2024.

Abstract
This study demonstrates the value of combining multiple non-invasive geophysical methods through a case study at a landslide along Highway 7 near Jasper, Arkansas, USA. Geophysical testing was conducted using Multichannel Analysis of Surface Waves (MASW), Horizontal to Vertical Spectral Ratio (HVSR), and Electrical Resistivity Tomography (ERT) along with select borings. Geophysical testing was aimed to provide a high-resolution and almost continuous image of subsurface conditions (including bedrock depth) for the slide area and to locate the groundwater table/highly saturated zones within the slide area which contribute to the slope movement. MASW revealed a highly variable depth to the weathered bedrock along the observed zone of displacement becoming shallower downslope. ERT detected saturated zones associated with observed seeps and springs in the area which were feeding water into the unstable zone. A low resistivity zone on the north side correlated to wet spots, while south of the highway saturation occurred near the deeper bedrock interface. Additionally, using a grid pattern HVSR approach, a high-resolution image of the shallow and complex bedrock topography was generated across the slide area providing valuable information for the repair design. Overall, the results of the combined geophysical approach provide a high-resolution image of landslide subsurface conditions which is critical for stability analyses and slope repair design. This integrated geophysical approach offers a more sustainable, rapid, and cost-effective solution for comprehensive landslide characterization and slope stability assessment when combined with conventional methods.
Abstract
This study demonstrates the value of combining multiple non-invasive geophysical methods through a case study at a landslide along Highway 7 near Jasper, Arkansas, USA. Geophysical [...]
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Use of Macroseismic Intensity Data to Validate the Ground Motion Prediction Model in Albania
A. Xhahysa*, M. Ceyhan, N. Kuka, E. Dushi, D. Koxhaj, K. Qoshi

ISC2024.

Abstract
Macroseismic observations are a valuable tool, that can be used for the verification of site response and attenuation. Hence, in the framework of a bilateral project supported by Central European Investment Fund and with the extensive support of Global Earthquake Model Foundation to update the national seismic hazard model of Albania, intensity maps that contained more than 6000 macroseismic observations for 168 shallow (h
Abstract
Macroseismic observations are a valuable tool, that can be used for the verification of site response and attenuation. Hence, in the framework of a bilateral project supported [...]
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In-Situ Cyclic Direct Shear Tests on Volcanic Soil in the Site of Landslide Due to Earthquake
A. Sato*, H. Hashimoto, R. Kuwano

ISC2024.

Abstract
Volcanic pumice soils are widely distributed in many countries. Mechanical properties of those need to be characterized since seismic ground motions can cause serious hazards such as large-scale slope failures and long-distance debris flows. Since volcanic pumice generally retains extremely high porosity and has a sensitive structure, the natural soil structure is easily broken during sampling or transportation. Therefore, it is preferable to conduct in-situ tests without disturbing the original structure of the soil. In this study, an in-situ direct shear test device was developed, and in-situ cyclic direct shear tests were performed on volcanic pumice (Ta-d). This pumice soil is considered to be the main cause of slope failure in Atsuma, Hokkaido, Japan, due to Easten Iburi earthquake in 2018. Laboratory direct shear tests were also conducted using undisturbed sample taken from the site. The results revealed that soil structure significantly affects shear strength. To evaluate the mechanical behavior of such sensitive soils, it is crucial to use specimens with as less disturbed specimens as possible. The newly developed in-situ direct shear test device was used to determine the cyclic shear strength of sensitive volcanic pumice soils.
Abstract
Volcanic pumice soils are widely distributed in many countries. Mechanical properties of those need to be characterized since seismic ground motions can cause serious hazards [...]
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MASW Joint Analysis of Rayleigh and Love Waves for Site Characterization
J. Hellín-Rodríguez, P. Martínez-Pagán*, I. Valverde-Palacios, A. García-Jerez, K. Suto, M. Martínez-Segura, J. Orta, J. Álvarez-Lozano

ISC2024.

Abstract
The determination of reliable shear-wave velocity models using Multichannel Analysis of Surface Waves (MASW) has increased importantly for site characterisation studies due to their use in geotechnical studies and regulations. The standard MASW approach is commonly based on the analysis of vertical component of Rayleigh waves, which can result in inaccurate and potentially erroneous interpretations by personal bias. Thus, we present the joint analysis of different and independent multi-component data based on Rayleigh and Love waves to obtain 2D Vs sections for site characterization. Those seismic data were recorded using a landstreamer consisting of 8 triaxial 4.5Hz geophones. To generate Rayleigh waves, the blows were given vertically on a plate, and for the Love waves the blows were given laterally on a horizontal wooden beam. A joint analysis of Rayleigh and Love waves data was conducted on seismic data recorded from the metropolitan area of Granada city (Spain) to generate their dispersion curves. This new approach enabled a proper identification of fundamental- and higher-mode surface waves facilitating the reliable reconstruction of subsurface Vs profiles through a robust joint inversion process. The MASW 1D Vs versus depth models were corroborated at several test sites by the information obtained from boreholes. Thus, the main geological formations could be inferred from MASW 2D Vs sections down to a depth of 30 meters, as well as the Vs30 parameter to perform a reliable seismic microzonation of the study area. This methodology provides a very well constrained inversion procedure capable of providing a robust subsurface Vs model for site characterization.
Abstract
The determination of reliable shear-wave velocity models using Multichannel Analysis of Surface Waves (MASW) has increased importantly for site characterisation studies due [...]
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Classification of an Exposed Mixed-Sediment Tidal Flat Using Synthetic Aperture Radar
J. Paprocki*, N. Stark, F. Falcone, H. Graber

ISC2024.

Abstract
Estuarine tidal flats represent a critical environment for maintaining healthy ecosystems. The geotechnical characterization of such environments is often challenging due to their soft nature and remote locations. Thus, the goal of this study is to explore the use of remotely sensed, high resolution (pixel resolution of ~0.5 m) synthetic aperture radar (SAR) data for characterizing these sediments. Towards this goal, the variability of sediment properties (median gain size, moisture content, fines content, and classification following the Unified Soil Classification System (USCS) were documented for a mixed tidal flat located on the Great Bay Esturay in New Hampshire, USA. A sediment classification scheme based on SAR, originally proposed by Gade et al. (2008), which utilizes the correlation length to characterize sediments based on the percentage of particles
Abstract
Estuarine tidal flats represent a critical environment for maintaining healthy ecosystems. The geotechnical characterization of such environments is often challenging due [...]
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3D Resistivity Survey of a Weathering Profile of Metamorphic Rocks in State of Pernambuco, Brazil
R. Coutinho*, C. Bortolozo, M. Andrade, F. Silva

ISC2024.

Abstract
This paper aims to study a weathering profile of crystalline rocks in the City of Camaragibe, State of Pernambuco, Brazil. For this purpose, a survey using electroresistivity was conducted. A regular mesh was performed aiming at 3D acquisition. The target area of the survey has 3 meters of depth (the Data Collection Platform, abbreviated as PCD) responsible for recording soil moisture information. An auger soil sampler was also made reaching a depth of 3 meters to describe and identify the substrate. The main objectives of the paper are to determine the geoelectrical characteristics of the materials and relate them to the strata previously identified and the soil moisture profiles. A goal was also to calculate moisture from the resistivity model and compare the results with those obtained by the PCD. The results allowed the creation of 3D geo-electric models, extending to a depth of 8 meters. It was also possible to create a 3D soil moisture model. It was possible to make a correlation between the geoelectric horizons and the layers of the rock alteration profile. The humidity results obtained by PCD and the resistivity model were examined, indicating favorable prospects for applying the method.
Abstract
This paper aims to study a weathering profile of crystalline rocks in the City of Camaragibe, State of Pernambuco, Brazil. For this purpose, a survey using electroresistivity [...]
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Muon Tomography for Mapping and Monitoring Tailings Storage Facilities
M. McLean, F. Scutti, R. Seikel, S. Krishnan, C. Webster, S. Collins, C. Goss, S. Palanisamy, P. Panchal, J. Donovan, A. Duffy, A. Christensen*

ISC2024.

Abstract
Tailings storage facilities pose an increasingly significant global challenge for mining companies. Given that tailings, the by-products of mine processing plants, demand meticulous management due to the potential hazards associated with storage facility failures, continuous attention is imperative. The repercussions of such incidents can lead to profound and enduring environmental damage in downstream regions. Therefore, consistently monitoring the structural stability of these facilities is paramount to ensure the safety and sustainability of both active mining sites and legacy mines. This paper introduces an innovative approach using muon tomography to analyze the internal density structures of tailings dams. The research, conducted at the BHP Prominent Hill Mine site in South Australia, presents a pioneering method and technology for examining the internal density distribution of tailings storage facilities using muons. Muons, being a natural source of radiation capable of generating X-ray-like scans of large structures, offer a distinctive opportunity to gain insights into the inner structure of tailings storage facilities. Moreover, this technology holds the potential to serve as a foundational platform for future research in the development of early warning systems for detecting structural changes.
Abstract
Tailings storage facilities pose an increasingly significant global challenge for mining companies. Given that tailings, the by-products of mine processing plants, demand [...]
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Site Characterization with Surface Waves in Kazakhstan
S. Abdialimi, D. Tuzelbayev, J. Kim, Y. Shokbarov, T. Ku, S. Moon*, V. Khomyakov

ISC2024.

Abstract
The South and Southeast Kazakhstan regions exhibit notable seismicity due to intricate tectonic interactions, albeit experiencing infrequent catastrophic earthquakes. Proximate to the convergence of the Eurasian and Indian plates, this region witnesses frequent seismic activity, particularly in cities like Almaty near mountainous terrain. Given the significant seismic activity, comprehensive site characterization is imperative. Traditionally, evaluating dynamic soil properties relies on conventional borehole logging techniques. However, the emergence of the multi-channel analysis of surface waves (MASW) offers advantages in cost, time efficiency, and non-invasiveness. Despite its benefits, MASW remains underutilized in Kazakhstan and is absent from local building codes, unlike neighboring CIS countries. This study aims to demonstrate the applicability of the MASW method for site characterization in Kazakhstan's seismic regions. Through extensive work, shear wave velocity (ðð ) values were estimated and compared with reference data obtained from seismic refraction and dilatometer testing. The results showed significant agreement, highlighting the suitability and effectiveness of the MASW method in Kazakhstan.
Abstract
The South and Southeast Kazakhstan regions exhibit notable seismicity due to intricate tectonic interactions, albeit experiencing infrequent catastrophic earthquakes. Proximate [...]
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Identification of density of earth-fill dam using muography
T. Shibata*, K. Takahashi, S. Nishimura, T. Shuku

ISC2024.

Abstract
In recent years, the high probability of large-scale earthquakes occurring in Japan has become a major social concern; and thus, it is urgent that countermeasures and maintenance be implemented for the protection of large-scale societal infrastructures from damage due to these earthquakes. When large-scale societal infrastructures are inspected, an internal diagnosis is required to evaluate the damage condition of the structures in order to see what countermeasures should be planned ahead of the occurrence of any earthquakes. However, conventional methods of diagnosis, such as groundpenetrating radar, have their limitations. Namely, they provide high-precision results in shallow areas, but results with reduced resolution in deeper regions. To overcome the shortcomings associated with these conventional methods of exploring depths out of the investigation range, one approach is to use muography1). This paper investigates the applicability of muon exploration techniques, using cosmic-ray muons, to probe the density of structures inside earth-fill dams.
Abstract
In recent years, the high probability of large-scale earthquakes occurring in Japan has become a major social concern; and thus, it is urgent that countermeasures and maintenance [...]
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Comprehensive geometric characterization of the subsurface using Microseismic Resonance: identifying sinkholes by modelling the bedrock surface and karstic features in a challenging environment
M. Green*, M. Jessop, P. Pires

ISC2024.

Abstract
This study presents a comprehensive assessment of the subsurface characteristics at a Unigel processing facility in Pedra Blanca, Sergipe, Brazil, utilizing Microseismic Resonance (MSR). The facility experienced the emergence of sinkholes and depressional features near critical infrastructure, prompting the need for a thorough subsurface characterization. MSR, a burgeoning microseismic technique, was employed due to its ability to geometrically characterize subsurface structures without the limitations of large geophone arrays. Fieldwork involved MSR data collection on a 10m by 10m grid over a 37.14 hectare area, complemented by borehole data and a gravity survey. Results revealed the intricacies of complex stratigraphy with Quaternary fluvial deposits overlying Early Cretaceous carbonates with karstic morphology. MSR data processing produced a holistic geometric model of the subsurface, including the identification of karstic features. Comparison with borehole data demonstrated high accuracy, with MSR Local Component (LC) data rendering a bedrock surface of approximately 99% accuracy. MSR Full Spectrum data (FS) is correlated with the gravity study validating the presence of karstic structures. This study showcases MSR as a powerful, non-invasive tool for rapid and accurate subsurface characterization, crucial for infrastructure security and environmental assessment
Abstract
This study presents a comprehensive assessment of the subsurface characteristics at a Unigel processing facility in Pedra Blanca, Sergipe, Brazil, utilizing Microseismic Resonance [...]
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Seismic Interferometry Technique for Characterization of Loose Soil Layers
S. Gokyer Erbis*, W. Marr, T. Bardainne, R. Tarnus

ISC2024.

Abstract
Surface wave tomography is a feasible method to provide complementary data to better understand the continuity of soil strata. It may also be used to determine best locations for invasive testing. Surface wave tomography methods are frequently used to delineate soil-rock interface and determine average shear wave velocity for seismic site class determination. Delineation within the soils layers where the change in seismic velocity within the soil layers are relatively small requires higher resolution data collection and enhanced processing methods than those used historically in surface wave tomography. This study uses a patented imaging and monitoring system based on the passive seismic interferometry technique augmented by active seismic sources at known locations. A dense nodal array of MEMs accelerometers were deployed at a site where known saturated loose materials exist. This paper presents shear wave velocity (Vs) data deduced from surface wave measurements where various, compression wave velocity (Vp) to Vs ratios were considered, especially showing the effect of Vp/Vs ratio, on the Vs data. This ratio which was traditionally assumed can have a significant effect on the inferred Vs. This paper also presents the comparison of deduced Vs data to measured Vs data by seismic cone penetration test and makes some recommendations for how to improve the methods to determine shear wave velocity in soft/loose soils.
Abstract
Surface wave tomography is a feasible method to provide complementary data to better understand the continuity of soil strata. It may also be used to determine best locations [...]
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Critical Speed of Railway Rections Obtained Using Surface Wave Analysis Tests
Á. Tijera*, R. Ruiz, J. Estaire

ISC2024.

Abstract
In recent years, there has been a global trend towards increasing the commercial speed of high-speed rail lines (HSLs) to cope with expected demand problems. Examples include the new HSLs projects for the UK and California, where the design speed reaches 400 km/h. Therefore, one of the biggest challenges currently faced by the railway sector is the determination of the critical speed value of railway sections. This is true both for future HSLs, due to their high design speeds, and for existing rail lines, due to the intended increase in commercial speed. The critical speed is that train speed that produces a dynamic amplification in the medium underlying the track, causing an amplification of the vertical movement of the track components and the supporting ground such that the stability of the infrastructure and the safety of passengers is compromised. This work sets out the methodology necessary to experimentally study the critical speed of a railway section by in situ applying surface wave spectral analysis techniques, SASW and MASW. The critical speed is determined by the lowest phase velocity of the local minima of the modal dispersion curves, or by the minimum of the apparent dispersion curve. Both methods are equivalent. This paper also presents the results obtained on some Spanish HSLs, both on tracks under construction and in operation. In the cases studied, the ballast layer is the one that presents the lowest shear wave velocity and the minimum of the dispersion curve, so it is the layer that determines the critical speed.
Abstract
In recent years, there has been a global trend towards increasing the commercial speed of high-speed rail lines (HSLs) to cope with expected demand problems. Examples include [...]
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Collapse Risk Evaluation of Subsurface Cavities in Pavements of Full-Scale Test Roads
R. Kuwano*, J. Kuwano, Y. Karasaki, R. Sera, T. Ihara

ISC2024.

Abstract
In order to solve the problem of subsurface cavities in urban areas, industry, government and academia carried out collaborative research over 2018-2020. In this joint research, analysis of existing cavity data, laboratory model experiments, numerical analysis, and full-scale field test, monitoring of the cavity in the road, etc. were conducted. In this study, a full-scale test road was constructed with artificial cavities installed to evaluate the risk of collapse in consideration of the road structure. A series of plate loading tests and falling weight deflectometer tests was conducted on the road surface above a cavity to understand the cavity behaviour. A surface wave survey was also conducted to evaluate the wave propagation on and around cavities. It was found to be reasonable to evaluate the collapse risk of subsurface cavities by the ratio of depth and width of cavities, in which the thickness of the pavement should be excluded from the depth.
Abstract
In order to solve the problem of subsurface cavities in urban areas, industry, government and academia carried out collaborative research over 2018-2020. In this joint research, [...]
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Bedrock Depth and Shear Wave Velocity Profile Estimation through HVSR Measurements in the Paraguayan Oriental Region
T. Stanichevsky*, M. Stanichevsky

ISC2024.

Abstract
The horizontal to vertical spectral ratio (HVSR) passive seismic method consists in processing measurements of ambient noise performed in three perpendicular directions. The objective is to define the primary resonant frequency of the site and estimate its amplification characteristics, which can be deduced from visible peaks or troughs in the HVSR curves. The shape of HVSR curves depend on the interaction of waves with the interface between sediments and the formation bedrock and, hence, can be related to the bedrock depth through derived relationships. This work presents 4 study cases in the Paraguayan oriental region where HVSR of microtremors were obtained. Furthermore, the obtained HVSR curves are inverted to get approximate shear wave velocity profiles under the assumption of sub-vertically propagating P and S body waves. HVSR curves were calculated through Geopsy (Wathelet et al. 2020) and the inversion process was made through OpenHVSR (Bignardi et al. 2016), both open-source tools for ambient vibration processing. In general, the method proves to give sufficient accurate estimates of sediment thickness and stratigraphy in typical Paraguayan formations of the oriental region and presents the advantage of being an economical and fast survey option, especially for early stages in a geotechnical campaign
Abstract
The horizontal to vertical spectral ratio (HVSR) passive seismic method consists in processing measurements of ambient noise performed in three perpendicular directions. The [...]
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Estimating the fundamental frequency of a sand tailings dam using the H/V spectral ratio method
C. Pasten*

ISC2024.

Abstract
This study estimates the fundamental frequency of an 85 m height sand tailings dam in Central Chile using the singlestation Horizontal-to-Vertical H/V Spectral Ratio Method (HVSR), calculated from seismic ambient noise and earthquake records. The dam was constructed by compacting hydraulically deposited sands classified from integral copper tailings, following the downstream construction method. A proper estimate of the dam fundamental frequency is critical for evaluating its seismic response and secure the safe tailings containment when subjected to intense ground motions generated by interface and intraslab earthquakes. Results from the HVSR method are compared with those of the Standard Spectral Ratio method (SSR) calculated as the ratio of the response of the dam crest and that recorded at the dam toe. The fundamental frequency of the dam is about 0.9 Hz in the dam central part away from the abutments, but differences in the vibration frequency are identified along the downstream slope and along the crest axis from the north to south abutment. An analytical relationship between the dam fundamental frequency, the dam height, and the shear wave velocity (Vs) profile is validated.
Abstract
This study estimates the fundamental frequency of an 85 m height sand tailings dam in Central Chile using the singlestation Horizontal-to-Vertical H/V Spectral Ratio Method [...]
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Standardization of Microtremor and Surface Wave Explorations
C. Konishi*, S. Tsuno, S. Senna, H. Yamanaka

ISC2024.

Abstract
In recent decades, microtremor and surface wave explorations have been widely applied for geotechnical investigations to estimate the S-wave velocity profile. The estimated S-wave velocity profile provides essential information for site characterization. Since we need to solve an inverse problem with the observed phase velocity of the surface waves to estimate the S-wave velocity profile, acquiring high-quality data is the most critical part. To ensure the data quality and the corresponding results, ISO 24057:2022, array measurement of microtremors to estimate shear wave velocity profile, was developed in 2022. The document specifies appropriate equipment, procedures, data analysis, and reporting for the array measurement of microtremors as a passive geotechnical survey. Since we cannot control the frequency contents in ambient noises, the frequency range with the high power may be limited in the microtremor explorations. In this situation, surface wave exploration can supplement this shortcoming. An example of combining the two results shows that it gives us a dispersion curve in a wide frequency range to estimate the S-wave velocity profile from shallow to deep subsurface structure. Developing a new ISO standard for surface wave explorations by following the microtremor exploration enhances the quality of the estimated S-wave velocity profile. Accordingly, we expect non-destructive and cost-effective investigations to be widely accepted worldwide.
Abstract
In recent decades, microtremor and surface wave explorations have been widely applied for geotechnical investigations to estimate the S-wave velocity profile. The estimated [...]
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Comprehensive Geophysical Assessment of Complex Geological Terrain in Kadapa Basin, India
S. Laxman, A. Kumar, A. Panjamani*

ISC2024.

Abstract
Traditional geotechnical investigation consisting of drilling many of boreholes, soil sampling and lab testing becomes uneconomical and time consuming for large and geologically intricate areas. In such cases, non-destructive geophysical surveys offer a time-efficient and economical solution, simultaneously providing an extensive areal coverage of subsurface profiling of geotechnical and geophysical properties. For the estimation of subsurface properties, three geophysical methods were employed in this study, which consisted of Ground Penetration Radar (GPR), Electrical Resistivity Tomography (ERT), and Multi-Channel Analysis of Surface Waves (MASW). Thus, the sub surface’s shear wave velocity profiles and apparent resistivity profiles were obtained. In the shallow depths, discontinuities and fractures were studied using electromagnetic radargrams from GPR. These tests were complemented with borehole exploration at the site. Results obtained from surface-based methods were validated against bore log data and visual observation of surface terrain. Subsequently, bore logs were integrated with the geophysical survey results to construct an integrated subsurface profile. The integrated subsurface profiles presented a three-layer subsurface structure consisting of dense gravelly sand in the top 1m, followed by strong rock formations and, ultimately, very strong fractured rocks. The extent of fracture in the rocks was studied using samples obtained from boreholes and available trenches at the test location. These findings helped compare the three methods and their applicability in delineating different subsurface layers in this study. GPR proves to be effective at shallow depths, while ERT and MASW help investigate deeper layers better. Further, this study offers critical insights for site characterization and engineering decisions in complex geological environments, improving the knowledge base of efficient and reliable subsurface evaluation techniques.
Abstract
Traditional geotechnical investigation consisting of drilling many of boreholes, soil sampling and lab testing becomes uneconomical and time consuming for large and geologically [...]
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Passive Seismics Monitoring Applied to Rock Block Stability in the Montserrat Massif
M. Janeras*, A. Macau, J. Andrés, F. Parera

ISC2024.

Abstract
The Montserrat Massif (Catalonia, NE of Spain) is a natural and cultural heritage where rockfall risk arises. Therefore, a risk mitigation plan is underway, including rockfall monitoring at different scales using different techniques. Particularly, the rock block A3-6, menacing the rack railway leading to the monastery, has been monitored since 2010 by extensometers that show the cyclic movement due to the annual thermal cycle, which is mainly recoverable, but small residual plastic derivations have been detected in a varying amount, along years. At the end of 2021, stabilization work has been carried out. The block has been monitored with passive seismic techniques before, during, and after these works in order to detect signs or evidence of evolving stability similar to previous experiences in the Alps. Two main results have been found. On the one hand, a slight difference in the recorded ambient noise between the potentially unstable block and the rear massif was detected, for both the H/V spectral ratio and the polar spectrogram. A characteristic resonance frequency of the block is observed around 20 Hz in the direction of the toppling instability mechanism. On the other hand, during the drilling works of the anchor bolts, it was possible to clearly detect when the drilling hammer crossed the rear joint of the block. This allows confirming the assumed geometry of the block and the required anchor length, as well as a qualitative assessment of the persistence of the joint and its mechanical contact.
Abstract
The Montserrat Massif (Catalonia, NE of Spain) is a natural and cultural heritage where rockfall risk arises. Therefore, a risk mitigation plan is underway, including rockfall [...]
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A Review of Laboratory Cone Penetration Test (CPT) in Unsaturated Soil
R. Li*, A. Leung, A. Yerro, C. Yu, Z. Jiang

ISC2024.

Abstract
Cone penetration testing (CPT) is a common site investigation method used to determine soil profiles and characterize in-situ soil properties. However, most of the existing interpretations of CPT data are established for dry or saturated soil. In recent years, studies have shown that ignoring the matric suction effect in unsaturated conditions during data interpretation could lead to biased soil characterization and soil property estimates. Still, due to the lack of fundamental understanding of the mechanics during cone penetration in unsaturated soils, accounting for the matric suction effect on the CPT data-soil properties/characterization is not clearly defined, and more laboratory testing in controlled environments is required to fill this gap in knowledge. Existing studies are different in terms of penetrometer diameters (dcpt), chamber dimensions, penetration rate, sample preparation, and suction control techniques. This paper first presents a review of the existing literature on CPTs performed in unsaturated soils in a controlled laboratory environment and discusses the effects of the aforementioned factors on the measured tip resistance. In addition, new results from centrifuge CPTs performed with controlled water levels in a rigid chamber are presented. For the purpose of such experiments, a 12.7 mm diameter miniature cone penetrometer was designed and fabricated to measure tip resistance values. Unsaturated CPT data show that the presence of matric suction in the soil tends to increase the tip resistance measurement during the cone penetration process. More tests are planned in the future to quantify this increase in CPT response with respect to other soil properties.
Abstract
Cone penetration testing (CPT) is a common site investigation method used to determine soil profiles and characterize in-situ soil properties. However, most of the existing [...]
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Interpretation of CPTu in Sensitive Fine-Grained Soils and Prediction of Residual Excess Pore Pressures in Consolidating Soils
P. Rahardjo*

ISC2024.

Abstract
Robertson (1986) soil classification on Sensitive Fine Grained Soils using CPTu is of interest since the variation of these soils include those of Consolidating Soils. However, the classification does not include into detail such as the influence of the existence of excess pore pressure prior to penetration testing or what is the contribution of the excess pore pressure to the total penetration resistance. Rahardjo et al (2008) studied this phenomena by extrapolation of the dissipation test data to determine the residual excess pore pressure which play an important role in CPTu testing. Further, Rahardjo et al (2016) continued investigation of the CPTu in Consolidating Soils using Bq, Bq* and Effective Stress Concept (Rahardjo et al. 2017). These findings have been very useful when using CPTu in very soft soils and ultrasoft soils where the undrained shear strength of the soils is very low. This paper is the results of several studies of CPTu testing in marine clays, lacustrine, ultrasoft soils or even peats. The author found that there is significant value of Bq and Bq*, hence are parameters of importance when dealing with soft soils and discussed in more detail. Recent applications are in very soft soils and peats in Sumatera and East Java mud eruption which are are also included.
Abstract
Robertson (1986) soil classification on Sensitive Fine Grained Soils using CPTu is of interest since the variation of these soils include those of Consolidating Soils. However, [...]
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Effective Friction Angle of Intermediate Grain Size Soils from Variable Rate Piezocone Penetration Test
Y. Liu, Z. Ouyang*

ISC2024.

Abstract
The effective friction angle (') is one of the most sought soil properties in geotechnical analysis and design that controls the fundamental soil strength behaviour. In this paper, A recently compiled database on intermediate grain size soils that were tested by variable rate piezocone penetration tests (VRCPTU) is used to examine an effective stress limit plasticity solution using piezocone data developed by NTH (Norwegian Institute of Technology) towards prediction of the geomaterials’ effective stress friction angle. It is shown that penetration rate during probe advancement influences the CPTU measured data and the drainage conditions can be indicated by corresponding normalized cone resistance and normalized porewater pressure measurement. Further analysis revealed that an input parameter termed the angle of plastification (β) from the CPTU solution correlates with soil contraction and dilation tendency and can be used to evaluate the 'of investigated soils, together with other normalized CPTU measurements. The tentative suggested formula of β for intermediate soils undergone VRCPTU testing is given based on the investigated database. A comprehensive testing program on the Yellow River Delta (YRD) silts in China and a silty geomaterial from northern Italy in Europe including benchmark laboratory triaxial tests on high quality samples, field and calibration chamber variable rate CPTU are showcased to demonstrate the verification of the NTH solution for evaluating 'of intermediate grain size soils.
Abstract
The effective friction angle (') is one of the most sought soil properties in geotechnical analysis and design that controls the fundamental soil strength behaviour. In [...]
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Effect on the Local Seismic Response Produced by the Construction of Rafted Piles Foundation
A. Trevisan, M. Lago*, F. Veronese

ISC2024.

Abstract
The seismic forces must be properly defined as required by European geotechnical design Codes. They are dependent from the morphological and stratigraphic characteristics that determine the local seismic response. The local seismic response can be evaluated using a simplified approach which is based on the classification of the subsoil according to the values of the shear wave propagation speed Vs. In the present case study, to complete the quay of the Rovigo Interporto (facing the River Canal Bianco), where a not negligible load is planned to be applied (50 kPa), has been designed a foundation with a large slab founded with not pre-casted reinforced concrete piles diameter 350 mm, drilled without removing soil, with vibrating casing, for settlement reduction (rafted piles as settlement reducers), on an area of approximately 6000 m2. The subsoil in this area, from geological and geotechnical point of view, is very variable and with layers of soft clay and loose sand or silt, with no presence of a dense and uniform sand layer where to transfer loads to. Moreover, the geotechnical model was complicated because of the presence of an old diaphragm wall with anchors (whose projection in plant covers around half of area) and was designed a large underground basin for hydraulic invariance. For this reason, an extensive campaign of CPTU and DMT tests, together with boreholes, sampling and laboratory tests was carried out in this area, which allowed a detailed characterization of the subsoil. Through direct measurement of seismic micro-tremors, carried out before and after the installation of the piles, has been evaluated the modification of the resonance frequency of the site, and modification of the propagation speed of the shear waves Vs induced by the slab over rafted piles over the entire area.
Abstract
The seismic forces must be properly defined as required by European geotechnical design Codes. They are dependent from the morphological and stratigraphic characteristics [...]
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Application of two analytical CPTU solutions to sensitive clay in Québec
P. Mayne, J. Greig, E. Cargill

ISC2024.

Abstract
A recent series of CPTU soundings in sensitive clay at the Louiseville Quebec test site has been published, allowing for the application of two closed-form analytical solutions based on: (1) effective stress limit plasticity and (2) hybrid cavity expansion-critical state methods. These are used for geoparameter interpretations including: effective stress friction angle, undrained shear strength, yield stress ratio, undrained rigidity index, and the coefficient of consolidation. Profiles of these soil parameters are compared with the benchmark values obtained from available series of previous and present laboratory testing programs at this site, including index testing, triaxial compression, and one-dimensional consolidation. Piezocone dissipation tests are used to assess the coefficient of consolidation which are validated by pressuremeter holding tests and lab oedometer tests. An empirical CPTU screening method identifies the Louiseville site as underlain by sensitive clay, versus a regular insensitive clay deposit, whereas soil behavior type charts using Q-F-Bq indicate the soils are either silt (zone 4) or regular clay (zone 3). The alternate screening method is verified by field vane and laboratory fall cone that show the clay is in fact sensitive (average St ≈ 22).
Abstract
A recent series of CPTU soundings in sensitive clay at the Louiseville Quebec test site has been published, allowing for the application of two closed-form analytical solutions [...]
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Back Analysed Interpretation of Yield Pressure from CPT using Bq
R. Kelly

ISC2024.

Abstract
A sand and gravel quarry has been backfilled with clays and silts washed from the quarried materials. The quarry is now being repurposed for an industrial development. Prefabricated vertical drains and surcharge have been installed to consolidate the soft sediments. Settlement plates and vibrating wire piezometers were installed to track the performance of the surcharge. CPTs have been performed adjacent to the settlement plate / VWP installations in order to confirm thickness of soft soils and to assess their yield pressure in order to facilitate back analyses. A Medusa dilatometer test was also performed as an independent measurement. Correlation between the CPT and DMT showed that Nkt was much smaller than the normal range and the Nkt factor appeared to be consistent with Bq interpretations. Similarly, the coefficients used to interpret yield pressure lay at the high end of the range and could be justified through correlation with Bq.
Abstract
A sand and gravel quarry has been backfilled with clays and silts washed from the quarried materials. The quarry is now being repurposed for an industrial development. Prefabricated [...]
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Investigation of the Relationship Between CPT Cone Resistance and Relative Density for a Range of Granular Soils
Y. Tian, B. Lehane

ISC2024.

Abstract
This paper presents an investigation of the effects of the properties of reconstituted granular soils on the relationship between CPT cone resistance (qc) and friction angle. The results from a large number of calibration chamber tests conducted at a number of stress levels involving soils with varying shapes, compressibility and mineralogy are presented. The paper also provides data recorded in a parallel series of investigations into the mechanical properties of the granular soils employed in the chamber tests. It is shown that the nature of granular deposits has a strong influence on the relationship between qc and relative density, and that there is a near linear relationship between the cone resistance and the critical state friction angle for sands reconstituted at a given density and stress level.
Abstract
This paper presents an investigation of the effects of the properties of reconstituted granular soils on the relationship between CPT cone resistance (qc) and friction angle. [...]
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Estimation of Cone Factor in Undrained Clay Using Spherical and Cylindrical Cavity Expansions
J. Yu, J. Zhu, M. Huang, Y. Lin, Z. Shi

ISC2024.

Abstract
The current cone factor of piezocone penetration tests is derived based on the assumption of elastic-perfectly plastic soil, and the soil rigidity index in the formula is empirically determined. This study introduces a novel in-situ testing equipment for determining both undrained shear strength and soil rigidity index of clays. The presented technique combines cone penetration test (CPT) and in-situ expansion. Indoor experiments are conducted to test the equipment. Corresponding theoretical analysis is carried out to interpret the experimental results. A hyperbolic hardening soil model for undrained clay is used throughout the derivation process so that the nonlinear stress-strain relation is taken into account. The ALE (Arbitrary Lagrangian Eulerian) large deformation finite element method is first employed to analyse the influence factors such as rigidity index, cone roughness, and in-situ stress anisotropy during the penetration process. The formula of cone factor is then proposed and correlated with the limit expanding pressure of the spherical cavity. The rationality of the cone factor is verified by comparing with the ALE analysis results and those published studies. Besides, the limit pressure of in-situ expansion tests is determined based on the load-displacement curve of cylindrical cavity expansion, Specific bearing capacity formula is derived and revised based on finite element analyses. Finally, undrained shear strength and soil rigidity index are solved based on the penetration and expansion results. Interpretation of experimental results shows that the proposed method in conjunction with the newly developed CPT can reasonably predict the undrained strength and rigidity index of soft soils.
Abstract
The current cone factor of piezocone penetration tests is derived based on the assumption of elastic-perfectly plastic soil, and the soil rigidity index in the formula is [...]
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Determination of Geotechnical Parameters of a Heterogeneous Tropical Soil Deposit Through Different Penetration Rate CPTu Data
V. Junqueira, J. Duarte

ISC2024.

Abstract
Assessing soil properties through geotechnical tests is a crucial activity to understand its behaviour. Field tests serve as a good approach to characterize the geotechnical behaviour of materials according to their in-situ condition. However, the interpretation of these tests often relies on empirical correlations, which can become complex when dealing with soils with notable heterogeneity. This paper objective is to determine the strength parameters and discuss the consolidation effects for a heterogeneous tropical soil deposit using data from field tests with different rates of penetration and laboratory tests. A layer identified as low-strength soil classified as silty-sand to silty-clay exhibited partial drainage during a standard-rate cone penetration. The approach proposed by Randolph and DeJong (2012) was used to determine the penetration rate necessary to mobilize an undrained behaviour of the material, since the cone penetration results shown that the material is mostly contractive and clay-like. CPTu tests were also conducted with penetration rates of 60 mm/s and 100 mm/s, to proper estimate the undrained shear strength (Su). These tests reinforced the presence of a preconsolidated upper layer, enabling the estimation for the overconsolidation ratio (OCR). For the normally consolidated portion of the residual soil, rapid tests that achieved a normalized velocity (V) associated with distinctly undrained penetration were used to derive the undrained shear strength (Su), with a cone factor (Nkt) estimated from standard-rate tests available. The geotechnical parameters estimated were then compared to the laboratory data results showing a convergence with the parameters estimated by the field tests.
Abstract
Assessing soil properties through geotechnical tests is a crucial activity to understand its behaviour. Field tests serve as a good approach to characterize the geotechnical [...]
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Towards a bio-inspired burrowing robot: Influence of the tip shape for soil vertical penetration.
I. Brodoline, F. Anselmucci*, H. Cheng, A. Sadeghi, V. Magnanimo

ISC2024.

Abstract
This research exploits biomimicry to engineer innovative solutions for soil exploration and tunnelling in complex environments where soil burrowing is the main challenge. Drawing inspiration from the effective burrowing mechanisms of earthworms, we focused on the development of a untethered bio-inspired earthworm- like robot that faithfully replicates the morphology and behavior of Lumbricus terrestris. While prior efforts have primarily explored the horizontal soil burrowing using small diameter probes, in this study we focused on the vertical burrowing capability of a 30 mm diameter robot body. We conducted an experimental parametric analysis of multiple robot’s tip shapes, concentrating on dry sand as the singular soil type. We inserted each tip at a constant speed and monitored the vertical force magnitude depending on the penetration depth. Higher aspect ratios showed better performance, reducing the penetration force compared to low ratios. Experiments showed that asymmetric tips, designed to enhance horizontal locomotion, do not compromise their performance in vertical burrowing. Additionally, we investigated soil fluidization through pressurized air, that effectively reduced shear resistance and facilitated tip penetration by up to 27%. These findings provide valuable insights into the forces requirements for penetrating deeper soil layers, and are essential for accurately design burrowing robots
Abstract
This research exploits biomimicry to engineer innovative solutions for soil exploration and tunnelling in complex environments where soil burrowing is the main challenge. [...]
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Punt d’equilibri entre la riquesa que aporta el turisme a una destinació i els costos que representa acollir turistes
J. Valls, M. Deulofeu

Abstracts_4rceec (2024). 205

Abstract
Per una banda, el sector es queixa de què no troba empleats i treballadors. Per una altra, els episodis del canvi climàtic malmeten nombrosos indrets de la costa catalana, alguns dels quals ja no es recuperen. Per una altra, la rendibilitat dels negocis, tot i ser mantinguda, es mostra inferior a altres Sectores. Malgrat això, el gaudi del territori i del patrimoni per part dels Natius i dels que venen a visitar-lo segueix sent una oportunitat de mantenir i millorar el que és propi i a la vegada una font de riquesa, d'empreses i de llocs de treballs important, en la mesura que lluny de malmetre el territori i el patrimoni l'enriqueixi. La pregunta de recerca és si existeix un punt d'equilibri entre la riquesa aportada pel turisme a una destinació i els costos econòmics, socials, mediambientals i altres que representen acollir turistes en aquest moment en el qual avença el canvi climàtic. Si aquest punt d'equilibri és identificable, la transició cap a un turisme verd i digital hauria de ser ràpida o espaiar-la en el temps. Per assolir aquest objectiu es planteja realitzar un seguit de dinàmiques de grup amb empresaris de l'hostaleria i del sector de l'acollida, així com amb experts en planificació turística. Es pretén obtenir dues respostes. La primera és on es troba el punt d'equilibri entre els ingressos reals que genera la gestió del turisme i les depeses de tota mena que significa La segona, davant la resposta afirmativa de l'anterior conclusió, com es realitza la transició i a quin ritme.
Abstract
Per una banda, el sector es queixa de què no troba empleats i treballadors. Per una altra, els episodis del canvi climàtic malmeten nombrosos indrets de la costa [...]
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Creixement i llegat a la pime catalana
O. López

Abstracts_4rceec (2024). 203

Abstract
Creixement i llegat a la pime catalana Segons l'Institut d'Estadística de Catalunya (Idescat), les petites i mitjanes empreses (PIMEs) a Catalunya representen aproximadament el 99,8% del total d'empreses. Aquestes empreses generen un 64,9% de l'ocupació total del sector privat i contribueixen amb un 61,4% del valor afegit brut (VAB) de l'economia catalana. Pel que fa al volum de facturació, les PIMEs representen un 61,5% del total (Idescat). Aquestes dades subratllen la importància de les PIMEs en l'economia catalana, destacant el seu paper clau en la creació d'ocupació i la generació de riquesa, però també mostren que el gran repte que tenim al davant és convertir aquesta força en un motor del creixement econòmic del país, sota dues premisses: el que es coneix internacionalment com el gran traspàs generacional de riquesa (empresarial, en aquest cas concret), unit al propi repte de l'estratègia de creixement dels negocis amb les noves generacions. Hi ha un patró que es repeteix a moltes PIMEs i no és la famosa frase segons la qual la primera generació la crea, la segona la fa créixer i la tercera se la ven. Això és buscar un culpable, enlloc d'una causa. Si anem a la causa, certs problemes es repeteixen a cada generació però, simplement, no totes l'afronten igual. És una constant que la majoria de PIMEs (i els seus líders) acostumen a veure un ràpid desenvolupament en els primers 5 anys (si fan les coses bé); un creixement continu (però més lent) en els propers 5 anys, i un estancament als darrers 5 anys. Això sovint ho veiem amb persones d'entre 45 i 55 anys; i, sota el meu punt de vista, és un dels obstacles empresarials que més em preocupen del nostre país, i que només es pot adreçar amb estratègia. Aquest informe aborda aquests grans reptes, centrant-nos des del primer moment en la identificació de les prioritats estratègiques que les PIMEs catalanes haurien d'adreçar per a, no només mantenir el ritme de creixement, sinó superar-lo a través d'un més alt valor afegit que repercuteixi en empreses més rendibles, més productives i més sostenibles en el temps. Tres àmbits (guanyar diners, guanyar temps i guanyar talent) que s'hauran de treballar amb estratègies de creixement que mirin al llegat que rebran les generacions futures, a través de l'enfocament en (1) afegir més valor i monetitzar-lo millor, de manera que guanyin rendibilitat; (2) fer els canvis adequats en les operacions per adaptar-se a mercats cada cop més exigents; i (3) convertir els empleats en gestors i líders, per a preparar les noves generacions d'empresaris des del planter. Les estratègies de creixement són perilloses. Hi ha líders empresarials que tendeixen a prioritzar el creixement ràpid, sense considerar la viabilitat ni la rendibilitat a llarg termini. Mentre d’altres es distreuen en temes menors per por a que guanyar volum signifiqui també guanyar problemes, ja siguin de temps, equip, producte, finances o mercat, entre d’altres. De la mateixa manera que si et trobes un bitllet de cent euros pel carrer, no decidiràs sortir cada dia a passejar a veure si te'n trobes un cada dia, les estratègies de creixement han tenir propòsit, ordre i, finalment, acció.
Abstract
Creixement i llegat a la pime catalana Segons l'Institut d'Estadística de Catalunya (Idescat), les petites i mitjanes empreses (PIMEs) a Catalunya representen [...]
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Un sistema de suport a la continuïtat empresarial: estratègia i resiliència
O. Alba, L. Sallent

Abstracts_4rceec (2024). 202

Abstract
Les petites i mitjanes empreses són el motor econòmic tant de Catalunya com d’Espanya i ara es troben no només amb el repte diari de l’examen del mercat, sinó que també han de conviure amb l’alta incertesa i complexitat, a la vegada que han de fer front als reptes derivats de la transformació digital, la lluita contra el canvi climàtic, la transició energètica, la igualtat de les persones, la manca de personal, les exigències del compliance i a una llarga i complexa teranyina normativa i burocràtica. És per això que considerem oportú no només afavorir la creació de noves empreses, sinó també dotar-nos de mecanismes que facilitin la continuïtat de les ja existents, com els sistemes de transmissió d’empreses (Reempresa), però també aquells que impulsin la transformació de les empreses, que les faci més fortes i resilients als canvis i imprevistos, i que n’assegurin la supervivència. Eines i instruments de prevenció del tancament d’empreses, esquemes predictius de l’economia que anticipin riscos d’alt impacte, i mecanismes de reestructuració i superació de possibles insolvències. Un sistema complet de suport a la continuïtat empresarial.
Abstract
Les petites i mitjanes empreses són el motor econòmic tant de Catalunya com d’Espanya i ara es troben no només amb el repte diari de l’examen [...]
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Presentació d’una innovadora tecnologia per a la detecció ràpida, a peu de platja, de la qualitat de les aigües de bany
M. de Torres, M. Figueras

Abstracts_4rceec (2024). 172
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A Digital Twin for Assessing the Remaining Useful Life of Offshore Wind Turbine Structures
R. Pacheco, J. García-Espinosa, D. Di Capua, A. Pastor

Journal of Marine Science and Engineering (2024). J. Mar. Sci. Eng. 2024, 12, 573

Abstract
This paper delves into the application of digital twin monitoring techniques for enhancing offshore floating wind turbine performance, with a detailed case study that uses open-source digital twin software. We explore the practical implementation of digital twins and their efficacy in optimizing operations and predictive maintenance, focusing on controlling the real-time structural state of composite wind turbine structures and forecasting the remaining useful life by tracking the fatigue state in the structure. Our findings emphasize digital twins’ potential as a valuable tool for renewable energy, driving efficiency and sustainability in offshore floating wind installations. These aspects, along with the aforementioned simulations, whether in real-time or forecasted, reduce costly and unnecessary inspections and scheduled maintenance.
Abstract
This paper delves into the application of digital twin monitoring techniques for enhancing offshore floating wind turbine performance, with a detailed case study that uses [...]
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Investigating the effect of cure schedules and cure initiators on sustainable composites for large offshore structures
J. Pothnis, K. Vélon, G. Bhatia, A. Hejjaji, A. Comer, A. Hejjaji

Investigating the effect of cure schedules and cure initiators on sustainable composites for large offshore structures (2024).

Abstract
This study evaluates the effect of post-cure schedules and cure initiator form on the mechanical properties of Glass fibre reinforced polymer (GFRP) laminates manufactured using an infusible reactive thermoplastic resin. Tensile, flexural, shear and dynamic mechanical analysis tests were conducted. Fractography was also performed. Specimens fabricated using liquid cure initiator and subjected to an elevated temperature post-cure were the control specimens. Ambient cured specimens decreased by no more than 12% in the case of tensile properties (modulus of 90◦ specimens) and by < 14.3% in the case of flexural properties (also modulus in 90◦ specimens). Furthermore, the difference in mechanical properties of 0◦ specimens fabricated using a powder cure initiator was observed to be within ≈ 7% of respective properties of control specimens. In the context of fabricating thick laminates for large-size offshore structures, the results suggest that an extended ambient post-cure cycle in conjunction with an initiator in powder form can be employed instead of an elevated temperature post-cure schedule with initiator in liquid form. This is economically beneficial since it eliminates infrastructure required for elevated temperature curing/post-curing. The risk of porosity induced due to liquid-based initiators is also avoided.
Abstract
This study evaluates the effect of post-cure schedules and cure initiator form on the mechanical properties of Glass fibre reinforced polymer (GFRP) laminates manufactured [...]
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Methodology and application to assess thermo-mechanical buckling in composite marine structures
R. Pacheco, D. Di Capua, J. García-Espinosa, O. Casals

Ocean Engineering (2023). Ocean Engineering, Volume 267, 1 January 2023, 113002

Abstract
This paper describes the research performed within the scope of H2020 project FIBRE4YARD in the development of a suitable thermo-mechanical framework to analyse composite structures under fire loads. The thermo-mechanical model uses the adiabatic temperature to obtain the through-thickness distribution of temperature of the triangular shell element, this formulation is able to predict phenomena such as pyrolysis, thermo-mechanical yielding and large displacements (non-linear buckling). An application case of a load-bearing section of a container ship is shown to demonstrate the correctness of the methodology, two type of materials are considered in the analysis, traditional materials such steel and advanced materials like fibre reinforced plastic (FRP) composites.
Abstract
This paper describes the research performed within the scope of H2020 project FIBRE4YARD in the development of a suitable thermo-mechanical framework to analyse composite [...]
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In-situ polymerizable thermoplastic and bio-epoxy based composites for offshore renewable energy applications.
G. Bhatia, A. Hejjaji, J. Pothnis, A. Portela, A. Comer

Fibregy OA (2024). Vol. Open Access Papers, 15

Abstract
This study evaluates various quasi-static mechanical properties of an in-situ polymerizable thermoplastic and a bio-based thermosetting composite comprising of non-crimp fabric reinforcement for potential use in the next generation of Offshore Wind and Tidal Power platforms. Mechanical properties are characterized under tensile, flexural, in-plane shear and interlaminar shear loading. Results reveal that the evaluated properties differ based upon matrix type. Fractographic evidence from scanning electron microscopy is used to explain the differences observed and was generally consistent in terms of revealing cohesive failure at the fiber-matrix interface for the thermoplastic composite and contrasting adhesive failure for the thermosetting composite. For glass fibre reinforcement, the thermoplastic composite is superior in terms of flexural 90° properties (+20%) while the thermosetting composite performed better in flexure 0° in terms of both strength (+15%) and modulus (+25%). In terms of interlaminar shear, the thermosetting composite exhibited higher strength (+14%) while Tensile and in-plane shear properties are similar for composites of both resin systems. Overall, neither matrix is superior in terms of overall mechanical properties and both matrices show promise as a stepping stone towards the use of more sustainable constituents in offshore structures.
Abstract
This study evaluates various quasi-static mechanical properties of an in-situ polymerizable thermoplastic and a bio-based thermosetting composite comprising of non-crimp fabric [...]
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