Documents published in 2024 : Scipedia

Evaluation of the Liquefaction Resistance of Sandy Soil for Shaking Table Tests
F. Castelli, S. Grasso, V. Lentini, M. Sammito*

ISC2024.

Abstract
Seismic liquefaction of loose saturated cohesionless soils is one of the most dangerous and catastrophic phenomena that involves a temporary loss of soil shear strength and stiffness as a consequence of increase pore pressure and reduced effective stress. Therefore, the evaluation of the excess pore pressure induced by shaking is important to predict the liquefaction behaviour of soils at a large scale. In this regard, the study provides the static and dynamic characterisation of a liquefiable sand. For this purpose, a laboratory testing programme, which included the execution of cyclic direct simple shear (CDSS) tests, was performed. The CDSS tests were carried out by means of the CDSS device at the Soil Dynamics and Geotechnical Engineering Laboratory of the University “Kore” of Enna (Italy). The device is designed to allow the soil specimen to be consolidated one-dimensionally and then sheared under constant volume conditions, which replicates the undrained shear condition of the soil specimen. The CDSS tests were conducted to evaluate the liquefaction resistance of the sand under several test conditions, i.e. initial relative density, vertical effective stress or cyclic stress ratios. Results of this study provide useful information for the geotechnical characterisation of the liquefiable sand to be used in shaking table tests at the Laboratory of Earthquake Engineering and Dynamic Analysis (L.E.D.A.) of the University “Kore” of Enna. The laboratory is equipped with a large biaxial laminar shear box for reduced-scale model tests developed to monitor liquefaction under two-dimensional shaking.
Abstract
Seismic liquefaction of loose saturated cohesionless soils is one of the most dangerous and catastrophic phenomena that involves a temporary loss of soil shear strength and [...]
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Liquefaction Assessment at Gravel Sites in Croatia Based on Vs and DPT Blow count
K. Rollins*

ISC2024.

Abstract
Liquefaction of loose saturated soil poses a significant threat to civil infrastructure during major earthquake events. Although liquefaction is most common in loose saturated sands, numerous liquefaction events in gravelly soil profiles have been reported. Assessing liquefaction resistance in gravelly soils is challenging because large particle sizes can interfere with the standard penetration test (SPT) and the cone penetration test (CPT). To address this challenge, recent efforts have focused on developing liquefaction triggering curves based on a large diameter (74 mm) dynamic cone penetrometer (DPT) blow count and normalized shear wave velocity, Vs1, which are less affected by gravel-sized particles. While based on field case histories, the curves are poorly constrained in some areas; additional case histories continue to be highly desirable. This paper describes an investigation of six gravel sites that liquefied in the 2020 Mw6.4, Petrinja, Croatia earthquake. At each site, boreholes were completed to define the soil profile, accompanied by DPT soundings and shear wave velocity profiling using the Multi-channel Analysis of Surface Waves (MASW) approach. At some sites, the DPT blow count increased through a silty clay surface layer even though the CPT cone resistance remained constant in this layer. This increase was thus attributed to side friction on the drill rods during penetration. Subsequent DPT tests performed after casing through the silty clay eliminated the rod friction. The measured blow count and shear wave velocities in the critical layers at these sites correctly predicted liquefaction using recent probabilistic DPT- and Vs1-based triggering curves
Abstract
Liquefaction of loose saturated soil poses a significant threat to civil infrastructure during major earthquake events. Although liquefaction is most common in loose saturated [...]
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Estimating the Small Strain Modulus G0 from DMT tests for loess subsoil as an example of the practical application of the non-seismic method
K. Nepelski*, T. Godlewski, M. Rudko, M. Witowski

ISC2024.

Abstract
Seismic tests in geotechnics are used to determine the maximum shear modulus, which is a parameter characterising the subsoil in the range of very small strains. Maximum shear modulus is employed in deformation analyses, in particular when using advanced constitutive models describing the behaviour of the subsoil. Deriving parameters indirectly is a routine procedure in geotechnics. In the absence of seismic measurements or at an early stage of analysis, knowing the correlation between the shear modulus and other parameters measured in situ makes it possible to approximately estimate these parameters. The value of the shear modulus is closely related to, among others, the density of the medium and the shear wave velocity, which is significantly influenced by the in situ vertical effective stress. Therefore, the rule is that the shear modulus increases with depth. The article presents the results of research on loess subsoil. Based on the seismic dilatometer tests (SDMT), a formula was established that allows the shear modulus to be estimated from non-seismic dilatometer tests (DMT). The results were compared to those obtained in laboratory tests such as bender element test (BET) in an advanced triaxial testing apparatus. Formulas were derived to estimate the maximum shear modulus in the loess subsoil based on the vertical geostatic stress and the value of the constrained modulus MDMT. Moreover, the results were analysed with reference to the results for other soils in Poland and validated in additional field tests.
Abstract
Seismic tests in geotechnics are used to determine the maximum shear modulus, which is a parameter characterising the subsoil in the range of very small strains. Maximum shear [...]
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Upgrading a resonant column apparatus to reliably measure specimen void ratio
C. Vulpe*

ISC2024.

Abstract
The small strain shear modulus of soils is an important design geotechnical parameter for a wide range of civil infrastructure applications. The small strain shear modulus can be determined by using elastic theory as a relationship between the soil density, which is expressed as a function of void ratio, and the measured shear wave velocity. Thus, the void ratio has a fundamental impact on the accuracy of the result. Laboratory testing involving resonant column apparatus allows for determining the changes in stiffness of soils with varying void ratios. Standard of-the-shelf resonant column apparatus works well for clayey soils but presents a number of limitations for coarse soils that makes accurate and reliable void ratio measurement difficult due to both pore fluid and (often) sample loss during removal from the equipment. This paper presents the development of a modular set-up which allows for complete specimen sealing at the end of shear wave velocity testing. The modular set-up along with the specimen can be removed from the resonant column apparatus and the void ratio can be determined by means of end-of-test-freezing similar to triaxial testing. From this, reliable small strain stiffness at well-determined void ratio can be computed. The void ratio measurements using the new modular set-up were compared to those from triaxial tests performed on identically prepared specimens. The difference in void ratio at any given isotropic confining stress was between 0.001 and 0.011.
Abstract
The small strain shear modulus of soils is an important design geotechnical parameter for a wide range of civil infrastructure applications. The small strain shear modulus [...]
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Engineering surveys for construction based on the concept of sustainability resource to external influences and nature-based solutions
V. Iegupov*, G. Strizhelchik, R. Goodary

ISC2024.

Abstract
The resource of resistance to external influences (or sustainability resources) is understood as the ability of natural or natural-technogenic objects and systems to withstand negative impacts and at the same time preserve and maintain their basic functional properties within acceptable or specified limits. The use of the concept of sustainability resources (SR) to assess the risk of a system leaving an acceptable state necessitates a revision of some methodological issues in surveys for construction. Traditionally, the purpose of research is to obtain initial data for design decisions and calculations for various purposes. We emphasize that the existing approach corresponds to the strategy of protection from hazardous processes, and the use of the SR concept to external influences is more consistent with the strategy to prevent negative consequences. In addition, social and environmental factors, combined with global climate change, also increase the risks of hydrometeorological hazards and associated floods, activation of landslides, erosion, and karst-suffusion processes. Reducing these risks has traditionally been achieved by implementing protective engineering controls (or gray infrastructure), but nature-based solutions (green and blue infrastructure) are increasingly being explored. This approach, in our opinion, corresponds to the goals of ensuring rational and sustainable interaction with the geological environment during construction. The methodology is discussed and examples of the use of nature-based solutions are given.
Abstract
The resource of resistance to external influences (or sustainability resources) is understood as the ability of natural or natural-technogenic objects and systems to withstand [...]
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Interface direct shear tests with novel binders
A. Boiero, E. Romero, M. Arroyo, G. Spagnoli*

ISC2024.

Abstract
In the offshore/marine environment, foundation elements need to be particularly long or wide in diameter in order to reach a competent bearing stratum through weak, low-strength sediments. The seabed conditions in oil&gas and renewable energy projects can be difficult, and the skin friction produced during driving operations could be insufficient to support the service loads placed on the structures. In this study, low-pressure injections of an acrylate gel and a colloidal silica product were made into reference sand, and interface direct shear tests were conducted under constant stiffness conditions. Conventional ground improvement projects already employ these items. Oedometer tests on untreated sand were used to evaluate the stiffness properties of the sand, which provided the foundation for determining the stiffness in the DSTCNS system. At an initial low relative density (Dro) of 0.40, Holcim sand samples were generated. This value is thought to be representative of the top zone of normal sediment profiles under offshore settings. Shearing the sand over a steel plate has been done by direct shear experiments conducted under constant normal stiffness conditions. The effects of injection have been compared using pre- and post-grout interface shear tests. The new binders' activity is causing an increase in skin friction, according to the results.
Abstract
In the offshore/marine environment, foundation elements need to be particularly long or wide in diameter in order to reach a competent bearing stratum through weak, low-strength [...]
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Evaluation of the challenges present in the obtaining, processing and interpreting useful data from offshore seismic cone penetration testing
T. Masters, I. Cazarez*, N. Tejani, G. Verbeek

ISC2024.

Abstract
The Seismic Cone Penetration Test (SCPT) is an essential tool for establishing in-situ shear wave velocity (ð£ð ), which is then used to establish profiles of Small Strain Shear Modulus (ðºððð¥), a direct input parameter to the design of offshore wind turbine foundations. Performance of SCPT offshore presents greater challenges than on land and each offshore site investigation contractor uses their own different non-standard equipment to try to address these challenges. This contributes to the multiple areas of uncertainty in the assessment of wave arrival time and distance, which can result in less reliable data sets. Additionally, a variety of data processing and interpretation methods are used across the industry, the benefits and limitations of which must be understood if one is to specify, plan or undertake such testing. The authors provide a review of methods of acquiring data, the equipment required and the different processing and interpretation methods available, specifically comparing true interval straight ray analyses with pseudo interval true ray path analyses and the different processing steps which can be taken to increase reliability in datasets.
Abstract
The Seismic Cone Penetration Test (SCPT) is an essential tool for establishing in-situ shear wave velocity (ð£ð ), which is then used to establish profiles of [...]
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Development of a 3D Ground Model for an Offshore Wind Farm with Complex Interlayering of Silty Soils
X. Peng*, Y. Gao, Y. Du, D. Wang, P. Li, X. Li, Y. Zhang

ISC2024.

Abstract
Three-dimensional (3D) ground models enable the visualization of complex subsurface conditions in offshore wind farms, which aid engineers in understanding the spatial morphologies and interrelations of different soil layers. Due to the large areas of offshore wind farms, 3D ground models established solely based on limited geotechnical data (e.g., boreholes and cone penetration tests) might lack the required accuracy. Geophysical data, particularly seismic profile data, is capable of revealing stratigraphic information and can be obtained at a relatively low cost. This study presents a case study in which a 3D ground model for an offshore wind farm located off the Southern China coast is developed through the integration of geotechnical and geophysical data. The wind farm features complex interlayering of silty materials below the soft Holocene marine deposits due to repeated sea level changes during the Quaternary period. This created significant challenges for developing a reliable ground model. In this paper, the challenges that were faced and solutions that were applied in this project are presented and discussed.
Abstract
Three-dimensional (3D) ground models enable the visualization of complex subsurface conditions in offshore wind farms, which aid engineers in understanding the spatial morphologies [...]
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Exploration for Wave Propagation Around Ground Loosening Using Discrete Element Method
K. Kuwashiro*, M. Otsubo, R. Kuwano

ISC2024.

Abstract
Ground loosening and subsurface cavities potentially cause ground cave-ins, even if they are deep in the ground. Loosened soil and cavities, for example, formed by shield tunnel excavation or breakage of underground pipes occur frequently. Recently, ground-penetrating radar method has been utilized to detect subsurface cavities, and studies such as dynamic wave surveys have been considered. However, these methods assume that cavities several meters deep can be detected by surface-based surveys, and do not target loosened soil directly above a deep tunnel. This contribution is a fundamental study aimed at detecting loosening depth in the ground, with the goal of measuring dynamic waves from the inside of a tunnel. To understand wave propagation and particle-scale response around loosened sandy soil, this study adopts the discrete element method (DEM) using cohesionless spherical particles. A series of DEM simulations are performed to understand how dynamic waves propagate or reflect around loosened sandy soil in comparison with dense ground without loosening.
Abstract
Ground loosening and subsurface cavities potentially cause ground cave-ins, even if they are deep in the ground. Loosened soil and cavities, for example, formed by shield [...]
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Statistical analysis between intensity measures at the bedrock and the seismic response of the site
A. Avellaneda, Y. Vargas-Alzate*, J. Vaunat, A. Di Mariano, A. Zapata-Franco

ISC2024.

Abstract
This research work focuses on the seismic response of sites considering uncertainties. There are two main objectives. The first consists on assessing the effectiveness of intensity measures to predict properties of the expected wave motion at the surface. According to recent studies, special attention has been paid to predicting velocity-related ground motion parameters, which are highly correlated to the nonlinear dynamic response of civil infrastructures. The second objective is to analyse the evolution of the dynamic properties of the soil because of seismic waves. The main database of acceleration records in Colombia has been analysed, as well as three soil profiles that correspond to real building projects designed and built in the same country. From this information, a series of site seismic response analyses have been carried out using the equivalent linear method. Then, using statistical regression techniques, the correlation between input variables (parameters of the seismic records) and output results (intensity measures at the surface, maximum soil deformations, damping and shear wave velocity variations) have been evaluated. The paper shows that a series of highly correlated variables can be used to incorporate, in a simplified manner, site effects in the analysis of seismic risk at a regional scale.
Abstract
This research work focuses on the seismic response of sites considering uncertainties. There are two main objectives. The first consists on assessing the effectiveness of [...]
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Field Site Characterization of a Coastal Aeolian Sandy Subgrade for a Proposed Tank Farm Site in Peru
J. Zamora*, M. Pando

ISC2024.

Abstract
Analysis of shallow foundations, pavements, and slabs-on-grade requires adequate site characterization of the nearsurface soils. Key properties required for the above are the soil stiffness and its nonlinearity. In this paper, we present the results of field site characterization at a coastal aeolian sand site located in Villa El Salvador, Peru, where large storage tanks are being proposed to be supported on concrete slabs-on-grade and shallow ring foundations. The site characterization included standard penetration tests (SPT), dynamic cone penetrometer (DCP) tests, lightweight deflectometer (LWD) testing, and geophysical tests such as multichannel analysis of surface waves (MASW), seismic refraction, and electrical resistivity. The paper focuses on estimating elastic soil stiffness (Es) values on the main bearing layer of the tanks. The observed large variability of Es estimates was associated with inherent soil variability at the site, the in-situ test method, and the use of empirical correlations between Es and different in-situ tests. Good elastic soil stiffness estimates for the bearing layer (Upper SP sand) were required to make reliable estimates of absolute and differential settlements for the tanks. Due to soil nonlinearity, the elastic stiffness values from the different methods decreased with increasing levels of shear strains associated with each test. Accordingly, the highest elastic stiffness values were from the MASW, followed by the LWD, and the lowest from SPT-based correlations. The soil stiffness estimates using SPT-based correlations yielded the highest variability due to the high uncertainty and low confidence of the empirical correlations between Es and SPT field values.
Abstract
Analysis of shallow foundations, pavements, and slabs-on-grade requires adequate site characterization of the nearsurface soils. Key properties required for the above are [...]
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Dynamic characterization of alluvial deposits through geophysical anda specialized test in Floridablanca santander
C. Buenahora Ballesteros*, D. Galvis Ballesteros, N. Amaya Perez, A. Martínez, L. Ortiz, M. Silva

ISC2024.

Abstract
The Metropolitan Area of Bucaramanga is located within one of the three seismic nests in the world and therefore presents a high seismic and geotechnical threat (INGEOMINAS, 2001), therefore certain zones, especially those with alluvial and colluvial deposits, have limitations for the development of infrastructure projects, unless a threat assessment is carried out that indicates otherwise or, in its absence, it is reduced to low levels with stabilization works. The thicknesses of these deposits vary from a few meters to two hundred meters and their definition and dynamic behavior (damping coefficient and terrain degradation curves), would allow analysis with special non-linear constitutive models to better understand their response to a possible earthquake and to ensure the stability of the structures and even an optimization based on a possible lower spectrum. A new two-tower housing project of up to 36 stories high is a perfect scenario to carry out a local seismic response study and perhaps transform the way future projects are designed. It should be noted that, given the acceptable stiffness and granular composition of the soils, it is difficult to take unaltered samples and the Colombian NSR-10 standard does not require local behavior studies and therefore its study has not been properly established. It is sought through geophysical tests and laboratory tests such as triaxial, resonant column and bender element to perform such characterization and to perform soil modeling that allows the calculation engineer to have the appropriate inputs for their analysis.
Abstract
The Metropolitan Area of Bucaramanga is located within one of the three seismic nests in the world and therefore presents a high seismic and geotechnical threat (INGEOMINAS, [...]
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Calculation of heights for local datum points of tide gauges in Albania referred to the average sea level and albageo program
B. Sina*, G. Hasko, E. Blloshmi

ISC2024.

Abstract
The accurate measurement and monitoring of sea levels are of paramount importance, especially for coastal regions like Albania, where sea level changes can have significant impacts on various aspects of life, including coastal infrastructure, ecosystems, and human settlements. This abstract provides an in-depth overview of a study focused on the calculation of heights of local datum points at tide gauges in Albania with reference to the average sea level, using the ALBAGEO3 program. Tide gauges play a crucial role in understanding the dynamic nature of sea levels. These instruments measure the height of the sea surface relative to a reference point, which is typically known as the local datum. The calculation of heights of local datum points is crucial for several reasons. Firstly, it provides insights into the relative sea level changes at different locations in Albania. It allows for the identification of areas that may be more vulnerable to such events, enabling betterinformed decision-making in terms of coastal management and disaster preparedness. Furthermore, accurate knowledge of local datum heights is essential for navigation and maritime activities. It ensures that nautical charts are up to date and that ships can safely navigate Albanian waters without the risk of running aground or encountering obstacles related to sea level changes. In summary, the study on the calculation of heights of local datum points at tide gauges in Albania, utilizing the ALBAGEO3 program, plays a pivotal role in advancing our understanding of sea level variations in this coastal nation. The accurate and reliable data generated through this research benefits not only the scientific community but also provides actionable insights for policymakers, urban planners, and other stakeholders involved in the sustainable development and protection of Albania's coastal areas.
Abstract
The accurate measurement and monitoring of sea levels are of paramount importance, especially for coastal regions like Albania, where sea level changes can have significant [...]
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Spatio-Temporal Prediction Surface Displacement in Urban Underground Excavation: A Case Study in Seville"
M. Bahri*, E. Mascort-Albea, R. Romero, C. Soriano Cuesta, A. Jaramillo Morilla

ISC2024.

Abstract
One of the primary challenges in excavating underground in urban areas is controlling and mitigating ground surface displacement caused by Earth Pressure Balance (EPB) tunneling. It is crucial to avoid damaging historical monuments and buildings in these areas. This paper presents a new method for predicting the surface displacement caused by EPB in Seville. A spatiotemporal dataset was generated for this study using numerical simulation in FLAC3D. The simulation replicates the excavation process of the Seville metro line in real-time, and records the surface displacements at selected points in the dataset. The last 20-time steps of excavation are predicted, and the first 80-time steps are chosen for training and tuning hyperparameters, as the dataset is spatiotemporal. A recurrent neural network (RNN) is used to detect and predict patterns between surface displacement and input features at different time steps and locations of the excavation. After fine-tuning the RNN, the model achieved an accuracy of 0.91 for the evaluated R-squared (R2), indicating its practicality for real-time prediction of surface displacement in underground excavations in Seville. The model's performance can be further improved with a larger data range. By deploying it as a hazard detector, the model can issue a warning if the ground displacement exceeds the limit, thereby preventing potential hazards. This approach can help control and mitigate potential hazards in underground excavations in historical cities.
Abstract
One of the primary challenges in excavating underground in urban areas is controlling and mitigating ground surface displacement caused by Earth Pressure Balance (EPB) tunneling. [...]
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Geotechnical monitoring at the speed of light: New insights from distributed acoustic sensing
S. Ouellet*, J. Dettmer, M. Lato, R. Crickmore, B. Dashwood, J. Chambers, A. Chavarria

ISC2024.

Abstract
Recent advances in distributed fibre optic sensing enable new opportunities in geotechnical monitoring and characterization. Distributed acoustic sensing (DAS) is a distributed fibre optic sensing technology relying on Rayleigh backscattering of light to detect and locate disturbances in near real-time along tens of kilometres of fibre optic cable. The dynamic strain sensing capabilities of DAS have prompted numerous research initiatives from the seismology community over the past decade. Although research on DAS for seismic applications is well established, studies on DAS for geotechnical monitoring applications are less common. Here, we present a summary of two recent case studies involving DAS for geotechnical monitoring. The first study considers a slow-moving landslide where DAS data were acquired over a three-day period of rainfall. The DAS aseismic strain and strain-rate data support the interpretation of the triggering and retrogression failure mechanism of the landslide. The second study considers an active mine site in northern Canada. Data were acquired from a cable installed ~1m below a tailings dam crest. Passive seismic interferometry was applied to DAS data to infer changes in seismic velocities in the uppermost several meters of the subsurface. These findings represent a first step towards advancing continuous monitoring techniques with fiber optic sensing technologies. However, further research is needed to improve our understanding of DAS performance for geotechnical monitoring applications over longer-term periods.
Abstract
Recent advances in distributed fibre optic sensing enable new opportunities in geotechnical monitoring and characterization. Distributed acoustic sensing (DAS) is a distributed [...]
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Effects of storage time on sample quality in Ballina clay
K. Ouyang, J. Pineda*

ISC2024.

Abstract
This paper explores the effects of the storage time on the engineering properties of Ballina clay, an estuarine silty clay that represents the soft soil deposits encountered along the eastern and southern Australian coastlines, which serves as foundation material for most of the country’s transport and energy infrastructure. An experimental program was carried out to evaluate the variation in soil compressibility and soil shear strength for tube specimens retrieved with an open sampler (Shelby tube) as well as an Osterberg fixed-piston sampler. Mechanical parameters obtained from tests performed immediately after sampling are compared against those measured over a period of 1 year, to assess the influence of the storage time. Results indicate that long-term storage has small influence on the quality of Ballina clay specimens in comparison with the mechanical disturbance caused during tube penetration and extraction, which is controlled by the sampler type.
Abstract
This paper explores the effects of the storage time on the engineering properties of Ballina clay, an estuarine silty clay that represents the soft soil deposits encountered [...]
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Relief well identification from satelite imagery using dual kernel filter unets
L. Zhang*, J. Tom, Z. Nick

ISC2024.

Abstract
Precise identification of levee relief well locations from satellite imagery can be challenging and time-consuming. In this research, we propose a novel approach utilizing a U-Net architecture to identify relief wells along flood control levees, as a proof of concept of combining freely available imagery with machine learning techniques. The goal of this research is to develop techniques to make infrastructure asset management more efficient by automating the process. Our study highlights the crucial role of the convolution kernel size in the U-Net architecture, which significantly influences the accuracy of the results. Larger convolution kernel sizes excel in capturing extensive contextual information from the input image, potentially leading to superior outcomes. However, training with larger kernels is computationally intensive. Conversely, smaller convolution kernel sizes excel in capturing local features. To strike a balance these considerations, we introduce a Dual Kernel Filter U-Net, which combines two U-Nets with distinct convolution kernel sizes, 3x3 and 11x11. This innovative approach aims to harness the strengths of both convolution kernel sizes to improve accuracy and overall performance. The proposed Dual kernel filter U-Net was trained and evaluated on a real dataset of relief wells from Google Earth imagery. Our evaluation results demonstrate that this model achieves an accuracy rate of 99.76% with training dataset 2626 satellite images. Notably, this significant accuracy enhancement is achieved without substantially increasing computational time, making it a promising advancement in satellite image analysis for object location identification and asset, and disaster management
Abstract
Precise identification of levee relief well locations from satellite imagery can be challenging and time-consuming. In this research, we propose a novel approach utilizing [...]
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Prediction of Future Settlement of Backfill at an Aggregate Mining Quarry Site in Irwindale, CA Using Numerical Method and Settlement Monitoring Data
A. Shafiee, C. Pappo*, M. Kamalzare

ISC2024.

Abstract
Future static settlement of a former aggregate mining quarry site in Irwindale, California is predicted based on the monitoring data and using numerical analyses that consider the total settlement of the deepest portion of the rockfill. The portion of quarry analyzed was backfilled with approximately 61 to 67 meters, has a volume of 2.6 million m3, and covers an area of 114,900 m2. The backfill material ranges from silty sand (SM) to silty gravel (GM) and was compacted to achieve an average relative compaction (RC) of 96%. The deepest fill area is currently being monitored with survey data to predict future 50-year settlement due to secondary compression. Settlement monument data from three different locations has been collected and made available starting from May 2009 up to now. A 3-dimensional model of the rockfill was used to determine an appropriate upper and lower bound of predicted future 50-year settlement from today in 13 stages and scenarios. The modified secondary compression index was estimated along with the modified compression index that was back calculated to match the field monitoring data. We could find good agreement between the field monitoring data and our numerical model when considering total settlement of the rockfill.
Abstract
Future static settlement of a former aggregate mining quarry site in Irwindale, California is predicted based on the monitoring data and using numerical analyses that consider [...]
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How to get a good match for consolidation coefficient
S. Peña Fernández, R. Gómez Escoubès*

ISC2024.

Abstract
It is difficult to get accurate magnitudes when dealing with consolidation coefficient, decisive when clays and clayey silts, are compressing, especially if secondary consolidation is in play. This is a typical condition in harbours when new areas are to be reclaimed to get more and more loading/unloading areas. There are several approaches to assess consolidation rate. The oedometer cell is the main lab test used to get the compressibility parameters. It is accepted that 24 hours is a good time for each pressure. However, some soils consolidate slowly, and they need more time. Especially when slope is far from horizontal. On the other hand, “true” consolidation coefficient is obtained when surpassing the preconsolidation pressure. Thus, values obtained below preconsolidation pressure are usually discarded. Horizontal coefficient of consolidation can be assessed with dissipation tests from piezocones. If piezometers are installed within the consolidating layer, comparing with the theoretical isochrones we may derive the “true” consolidation coefficient. If settlements are measured, a comparison with theoretical ones can be informed on the predominant consolidation phenomenon. Much care is to be applied and not misunderstand the process in play. Dissipation tests give way to much higher consolidation values than laboratory tests. This could be due to anisotropic effects, but the main reason is that dissipation occurs in a reloading process, while oedometer tests are in primary consolidation, at least from the preconsolidation pressure and on. This paper shows some ideas to properly assess the process involving consolidation.
Abstract
It is difficult to get accurate magnitudes when dealing with consolidation coefficient, decisive when clays and clayey silts, are compressing, especially if secondary consolidation [...]
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Site Characterization of a Restored Coastal Dune and Beach
B. Harris*, J. Hubler, J. Shawler, N. Stark, P. Tereszkiewics, J. Moore, W. Caldwell, L. Provost

ISC2024.

Abstract
Coastal beach and dune ecosystems are critically important for shoreline protection and significant resources have been allocated to their conservation. Dune vegetation is known to modify site response to wind, waves, and storms, but little focus has been given to understanding how belowground sediment structures enhance dune stability. A first step in addressing this knowledge gap is to determine optimal methods to measure subsurface sediment properties in onshore sandy environments. Our team performed a comparison of geotechnical and geophysical methods on a restored beach and dune system on Florida’s Atlantic coast. Methods included two types of dynamic cone penetrometer (DCP) systems, a multi-channel analysis of surface wave (MASW) system, a ground penetrating radar (GPR), soil vibracores, and grain size analyses. Two transects were investigated, a 50-meter cross-shore transect and an intersecting 20-meter along-shore transect. The transects were selected to study the gradient of sediment properties from the swash zone to the high dune. Key findings from this study were that the PANDA DCP provided a higher resolution of measurements compared to the standard DCP, which is extremely advantageous in the shallower, less consolidated soils. MASW shear wave velocity results showed similar trends to the DCP cone tip resistance and allowed for measurement of stiffer soils where the DCP reached refusal. In addition, the results from the DCP, GPR and vibracores compared well. Thus, the use of the DCP and GPR systems as minimally intrusive testing options in fragile dune systems was verified.
Abstract
Coastal beach and dune ecosystems are critically important for shoreline protection and significant resources have been allocated to their conservation. Dune vegetation is [...]
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Combined Monitoring Remote Sensing Systems: Ground-Based SSR and Satellite-Based SAR
C. Vulpe*, A. Fourie, L. Probst, H. Larkin, S. Donegan, D. Holden, G. Hanssens, A. Dianoff, E. Ronne, A. Lloyd, B. Conway-Jones

ISC2024.

Abstract
A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to investigate relative changes in displacement experienced by a mine waste storage facility. The relative changes in displacements along the InSAR line-of-sight (LoS) were compared to the relative changes in displacement provided by the ground-based SSR LoS. Although the two LoS are different, this study showed good agreement between the magnitude of relative displacements observed by both remote sensing technologies on the slope of the facility. Additionally, the study looked at the effectiveness of InSAR and SSR on capturing relatively shallow operational works undertaken on the tailings storage facility slope. Results showed that SSR is able to provide near real-time information about progressive trends in displacements and alert mine site personnel of potential areas that might need attention. InSAR could detect anomalies in surface deformations during the period when SSR did, but the radar signal was sufficiently low to not unequivocally attribute these responses to real surface deformations
Abstract
A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to [...]
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Improvement of Apparatus for Sampling and Cone Penetration Test
R. Fujikata*, K. Tani, S. Nomura

ISC2024.

Abstract
In this paper, a new innovative method of geotechnical investigation applicable to seafloor is proposed. This method is the improved version of Sampling and Cone Penetration Test (S&CPT) to evaluate geotechnical properties by Cone Penetration Test (CPT) while collecting continuous samples quickly and inexpensively for offshore geotechnical investigations. In the previous study, demonstration tests on soft cohesive soil were conducted, and some problems were found. The purpose of this study is to modify the sampler to improve penetrability, sampling performance, workability and to examine the applicability for cohesionless soils. Using the improved samplers, demonstration tests were conducted at two sand sites (loose and medium-dense) in Japan. The results of each test were used to examine: (1) sampling performance, and (2) workability. As a result, the following conclusions are drawn: 1) In loose sand, sampling of several meters is possible. In medium-dense sand, the same level of sampling may be possible by providing an appropriate shoe to prevent blockage at the sampler tip. 2) The workability of the proposed apparatus is very high compared to the conventional Cone Penetration Test and Standard Penetration Test.
Abstract
In this paper, a new innovative method of geotechnical investigation applicable to seafloor is proposed. This method is the improved version of Sampling and Cone Penetration [...]
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Detection of cavities in an urban environment: Case of M’Rara region (Northeast of Algeria)
B. Bouyahiaoui*, A. Abtout

ISC2024.

Abstract
Micro-gravimetry emerges as the most appropriate geophysical technique for cavity detection in urban or industrial settings, as it remains unaffected by surrounding electromagnetic influences. The presented study investigates the occurrence of fissures, land subsidence, collapse events, and their potential association with the formation of cavities at depth. These phenomena were observed near a sealed hydraulic drilling site located in the M’Rara area within the Northeast Algerian Sahara basin. This drilling operation was sealed off due to the inflow of saline water, with a salt layer identified at a depth of 936 m according to the stratigraphic column. A gravimetric survey was conducted to image the lateral and vertical density variation. The resulting gravimetric image allows in comprehending the observed geological phenomena and their potential correlation with the presence of cavities at the salt layer.
Abstract
Micro-gravimetry emerges as the most appropriate geophysical technique for cavity detection in urban or industrial settings, as it remains unaffected by surrounding electromagnetic [...]
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A Cylindrical Cavity Expansion Test on Sand
S. Nachum*, M. Talesnick, M. Ghafghazi

ISC2024.

Abstract
Cylindrical cavity expansion is one of the fundamental boundary value problems in geotechnical engineering used as a simplified analogue to the pressuremeter test, pile driving and the Cone Penetration Test. Much of the popularity of cavity expansion comes from the simplicity of modelling it numerically. All numerical models require verification and validation, but doing so for cavity expansion has been limited due the relatively small amount of physical modelling of the problem. Past cavity expansion tests in calibration chambers have often been limited in range of strains, diameter to length ratio, and the amount and type of measurements made. This paper describes a calibration chamber set up used to perform cylindrical cavity expansion tests in a dry fine sand. Instead of attempting to replicate a specific application (e.g., pressuremeter test), the goal was to create a near-perfect cylindrical cavity expansion model, with in-soil measurement of stresses and strains, to serve as baseline data for validation of numerical models. The experimental set up is described, the material properties are summarized, and results of a cavity expansion tests are presented and discussed.
Abstract
Cylindrical cavity expansion is one of the fundamental boundary value problems in geotechnical engineering used as a simplified analogue to the pressuremeter test, pile driving [...]
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How much does the spatial variability of CPTu measurements affect the hydro-mechanical variables' estimation?
G. Vessia*, D. Di Curzio, W. Pula

ISC2024.

Abstract
Using CPTu profiles for subsoil characterisation, transformation equations must be used to obtain the hydro-mechanical properties for structures and infrastructure designing. Additionally, the uncertainty and the spatial variability of measured parameters must be taken into account for a reliable geotechnical design. In this work, we used a Stochastic Simulation approach to define reliable 3D models of two geotechnical designing variables for granular soils (friction angle–’ and the Darcy permeability coefficient–k) from tip resistance (qc), sleeve friction (fs), and pore pressure (u2) profiles. The selected method – the Sequential Gaussian Co-Simulation (SGCS) – provided reliable optimized 3D models of the spatial distribution of the variables of interest and allowed quantifying the propagation of the estimation uncertainty associated with the raw measurement models through the transformation equations. Overestimation (OE) and Underestimation (UE) percentages for a confidence interval of 68% were calculated throughout the 3D model: granular soils showed a larger uncertainty than fine soils concerning the measured variables (qc, fs, and u2). In granular soils, the measured variable uncertainty varies up to 100% but the derived variables show different behavior: ’ shows UE and OE less than 25% while k reaches 100%. These differences in the propagated uncertainties depend on the transformation equations and the measured variable dependence.
Abstract
Using CPTu profiles for subsoil characterisation, transformation equations must be used to obtain the hydro-mechanical properties for structures and infrastructure designing. [...]
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A practical method to derive shear modulus from pressumereter tests in clay
J. Habert*, A. Lopes

ISC2024.

Abstract
Pressuremeter tests are an efficient tool to derive shear modulus of ground, and its decay with shear strain. Non-linear behaviour of ground during cavity expansion, and its consequence on shear modulus and stress with the distance to the pressuremeter cavity, have to be taken into account. For tests in fine soils, for which constant volume can be assumed during the test, retrofitting of unload-reload loops based on closed form solutions integrating the non-linear elastic behaviour can be implemented. In a first phase, this paper presents a practical straightforward method to derive shear modulus decay with shear strain based on the cylindric cavity expansion theory including non-linear elasticity under undrained conditions and hyperbolic ground behaviour. In a second phase, the method is applied step by step to a pressuremeter test in clay with unload-reload loops. Finally, on a third and last phase, this paper compares the previous results from to i) other interpretation methods integrating prior strains transformations, but also to ii) other investigation tests providing the initial shear modulus G0 associated with very small strain levels or the shear modulus decay with strain level.
Abstract
Pressuremeter tests are an efficient tool to derive shear modulus of ground, and its decay with shear strain. Non-linear behaviour of ground during cavity expansion, and its [...]
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Correlations Between The Pressuremeter And The Rigid Dilatometer Parameters In Soils
C. Jacquard*, T. Besson, M. Rispal, P. Reiffsteck, F. Szymkiewicz

ISC2024.

Abstract
The Dilatometer Fondasol Test (DFT) is a unidirectional loading test in a borehole that provides an in-situ stress-strain curve. Two rigid shells are spread in the soil at a constant displacement rate by several small hydraulic jacks. First results using this probe in soils were obtained by Besson (2022) who also provided methods to compute from the stress-strain curve both a pseudo-elastic modulus and a limit stress. However, additional data were required to establish strong correlations between the dilatometer parameters and the pressuremeter parameters. This paper introduces new results obtained in various sites in France and synthetises all the results obtained so far. For each site, pressuremeter soundings and dilatometer soundings are carried out in pairs using the same drilling methods. DFT and PMT are performed at the same depths and at the same strain rate. For the computation of moduli and limit stresses, semi-automatic methods are employed to prevent subjective interpretations. Correlations are proposed between the dilatometer modulus and the pressuremeter modulus as well as between the dilatometer limit stress and the pressuremeter limit pressure. The established correlations, along with their limitations, are interpreted.
Abstract
The Dilatometer Fondasol Test (DFT) is a unidirectional loading test in a borehole that provides an in-situ stress-strain curve. Two rigid shells are spread in the soil at [...]
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Comparative tests between Texam and Menard Pressuremeters
L. Marcil*, G. Sedran

ISC2024.

Abstract
Two testing programs were undertaken for comparing results of the Texam and Menard pressuremeters with regards to the deformation modulus (E) and limit pressure (Pl). Two configurations of the Texam pressuremeter were used; one with a probe fitted with metal rings, the other with a probe fitted with polymer (vulcolan) rings. The results of the first program carried out in laboratory and presented in a previous article, have been completed and are presented here. The second testing program have been undertaken in the field. A total of 41 tests were completed in three boreholes in silty and clay materials. The comparative tests produced excellent correlations in the laboratory, with regression coefficients (R2) of 0.99, and fairly good correlations in the field (R2 ranging fron 0.64 to 0.73). The main findings are that the Texam produces equivalent or conservative results. More specifically : (1) the Texam with metal-ring probe produces comparable moduli values, (2) the Texam with polymer-ring probe produces lower moduli values, and (3) the two configurations of Texam produce lower limit pressures. The observed differences range between 10 to 20 %. Equivalence factors have been proposed.
Abstract
Two testing programs were undertaken for comparing results of the Texam and Menard pressuremeters with regards to the deformation modulus (E) and limit pressure (Pl). Two [...]
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Deriving Strength Parameters of Granitic Residual Soils from Menard Pressuremeter Tests
C. Rodrigues*, N. Cruz, C. Mateus

ISC2024.

Abstract
Residual soils are non-textbook materials that are hard to be modelled by traditional soil mechanics, which creates serious difficulties in the in-situ test interpretations and the consequent applications to geotechnical design. This is due to the presence of a cementation structure that is responsible for a cohesive-frictional behaviour of these soils, meaning that two strength parameters must be derived to represent the overall strength. Furthermore, cementation structure also deeply affects the stiffness behaviour, deviating from typical response of transported soils. The common interpretation of in-situ tests usually considers extreme behaviours represented by only one parameter, namely undrained cohesion for clays and angle of shearing resistance for sands, which naturally do not work in these cohesive-frictional materials. For this purpose, only tests that take two or more independent measurements can be used to solve this problem, as it is the case of SCPTu, SDMT and PMT tests, while SPT and DPSH tests cannot be effective in this determination. Portuguese research institutions have been looking over the granitic residual soil characterization through specific research works, from which resulted several publications on the subject. Following previous research works of calibration with (S)DMT (Cruz, 2010) and (S)CPTu (Cruz et al. 2018) tests performed in Polytechnic Institute of Guarda (IPG), Portugal, a new research frame was developed to settle a methodology for obtaining strength parameters of granitic residual soils from pressuremeter tests (PMT), which is presented and discussed herein.
Abstract
Residual soils are non-textbook materials that are hard to be modelled by traditional soil mechanics, which creates serious difficulties in the in-situ test interpretations [...]
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Expansion test with one unload-reload loop and pore pressure measurement, first interpretation of dissipation tests, Larivot site
V. Savatier, P. Reiffsteck*, A. Philippe, M. Peronne

ISC2024.

Abstract
This paper presents an interpretation of cyclic pressuremeter tests with pore pressure measurement performed at Larivot bridge site (French Guyana). In cohesive soils, test results are in accordance with the pressuremeter theory. The times at 50% dissipation correlate closely with those obtained from dissipation tests performed using a piezocone in the immediate vicinity.
Abstract
This paper presents an interpretation of cyclic pressuremeter tests with pore pressure measurement performed at Larivot bridge site (French Guyana). In cohesive soils, test [...]
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Interpretation of the undrained pressuremeter test in unsaturated condition
J. Monnet*, L. Boutonnier

ISC2024.

Abstract
The pressuremeter measures both the pressuremeter modulus and the limit pressure, which are used to estimate the bearing capacity of the foundation according to different standards. The results of the pressuremeter test include the pLM limit pressure and the EM pressuremeter modulus. These quantities cannot be directly input as data for geotechnical calculations using Finite Elements or Finite Differences in the study of civil engineering structures such as retaining walls, tunnels, embankments, and excavations. These modern calculation methods require, at a minimum, knowledge of the mechanical characteristics of the soil, including elasticity (with Young’s modulus (E) and the Poisson ratio ()) and resistance (with cohesion (c’) and the angle of friction (’)). This study is devoted to the interpretation of the pressuremeter test so that it is possible to use it for the determination of the mechanical characteristics of the soil. When the pressuremeter test is carried out into clay, it appears pore pressure during the test when only shearing is applied. In summary, understanding pore pressure and interpreting measurements to determine the effective shear modulus are crucial for geotechnical engineering and subsurface exploration. Effective shear modulus can differ significantly from the value determined solely based on total pressure. This study provides the theoretical value of the Skempton coefficient B. Additionally, it proposes an interpretation theory for the pressuremeter test in clay. Finally, the theory is validated through a comparison with tests performed in London clay at a depth of 20.6 meters
Abstract
The pressuremeter measures both the pressuremeter modulus and the limit pressure, which are used to estimate the bearing capacity of the foundation according to different [...]
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CPTU Onshore Testing with Pre-Drilling and/or Re-Drilling of the Ground at the Port of Barcelona. Lessons Learned
J. Rubio, L. Casas*

ISC2024.

Abstract
SOCOTEC Spain, together with our partner GEM (Geotecnia y Exploraciones Marítimas), has been performing one of the largest geotechnical survey investigations in the development of new areas in the Port of Barcelona. This investigation includes multiple onshore and offshore tests including drilling and sampling, CPTU, and both in situ and laboratory testing. The CPTU (Cone Penetration Test with pore pressure measurement) is currently one of the most widely used in situ tests for soil characterization. Regarding the regularization of this test, all Standards specify the technical requirements of the equipment, the method of execution of the field test and the presentation of results and minimum corrections that have to be considered when performing and interpreting a CPTU. However, the current regulations do not refer to the methodology to be followed for the pre-drilling and/or re-drilling of the ground before a CPTU test, which is a common and operationally ‘standard’ procedure. In this sense, during the onsite research campaign, the results obtained in numerous onshore and offshore CPTU tests have been analyzed and, a variation in the pore pressure data recorded in the onshore CPTU tests associated with the pre-drilling and/or re-drilling operations has been identified. For this reason, the purpose of the paper is to highlight the need for a standardized procedure to execute this type of drilling operations and/or the necessary corrections to be taken into account during the interpretations of the results obtained in order to correct the anomalies associated with the injection of an artificial water flow.
Abstract
SOCOTEC Spain, together with our partner GEM (Geotecnia y Exploraciones Marítimas), has been performing one of the largest geotechnical survey investigations in the development [...]
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Impact of better pressuremeter interpretation on the cost of geotechnical structures
R. Granjon*, J. Monnet

ISC2024.

Abstract
This paper deals with the contribution of the realistic evaluation of the pressuremeter probe inflation mechanism and its technical and economic consequences for the project manager. This new approach allows to, within the framework of the Caderousse PCH studies, to significantly optimize the sheet pile modulus used by reassessing the soil characteristics in a more detailed way.
Abstract
This paper deals with the contribution of the realistic evaluation of the pressuremeter probe inflation mechanism and its technical and economic consequences for the project [...]
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PLENARY LECTURE - The Legacy of Michele Jamiolkowski to Geotechnical Engineering
S. Foti*, R. Salgado, R. Lancellotta

ISC2024.

Abstract
Michele Jamiolkowski was deeply interested in many topics in geotechnical engineering. The link between his many contributions to the discipline was his deep appreciation for the need to develop techniques for predicting the performance of real structures. This focus on real structures was pervasive in all of his research, and led to his attention to experimental investigation of natural soils. Jamiolkowski recognized the importance of in situ tests to site characterization of natural soils, and consequently this paper focuses on this topic. Jamiolkowski was involved in many challenging projects, and he always considered each project as an occasion to improve the state of the art, to develop novel approaches in site characterization, to develop new in situ test interpretation methods, and to obtain quality experimental data. The paper summarizes major improvements to the state of the art that resulted from his contributions, as well lessons learned from major and iconic projects in which Jamiolkowski was involved.
Abstract
Michele Jamiolkowski was deeply interested in many topics in geotechnical engineering. The link between his many contributions to the discipline was his deep appreciation [...]
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PLENARY LECTURE - Instrumental Dynamic Penetrometers for Geotechnical Characterization
P. Breul, P. Reiffsteck

ISC2024.

Abstract
The dynamic penetrometer is a common technique in geotechnical exploration and widely deployed throughout the world. However, while this technique has many advantages, it also has several disadvantages that can hinder its use and development. Indeed, it has evolved little, and its application has sometimes remained "rustic". But in recent years with the development of sensors, interpretation methods and digital technology, this technique has been adapted to improve the quality of measurement, the understanding of the phenomena occurring during the test and its exploitation. This article presents the recent developments and adaptations of this technique and their potential. After a brief review of the principle, history, and current limitations of the technique, we look at recent technological developments and the latest advances in terms of interpreting and using the test.
Abstract
The dynamic penetrometer is a common technique in geotechnical exploration and widely deployed throughout the world. However, while this technique has many advantages, it [...]
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PLENARY LECTURE - Simulation-aided geotechnical site investigation
L. Monforte*, M. Arroyo, A. Gens

ISC2024.

Abstract
With the advancement of computational geomechanics over the past decades, most of the activities typical of site characterization, such as in situ testing or sampling, can be realistically simulated using appropriate constitutive models and balance equations for geomaterials. These numerical simulations are not only informative of the processes that take place during testing but can be used to assess the reliability of current practice empirical interpretation techniques or even propose new interpretation techniques. In this paper, we present two numerical analyses of long-standing geotechnical problems in which new insights are gained by means of advanced numerical modelling. The first analysis corresponds to cone penetration testing in undrained, brittle geomaterials; we describe the effect of the constitutive parameters on cone metrics, and we propose a novel procedure to estimate the initial state parameter from CPTu based on a wide-ranging parametric analysis. The second analysis involves tube sampling in undrained geomaterials. A total stress analysis allows us to describe the kinematics of the soil during tube insertion and evaluate the effect of the tube geometry on the strain path of the problem. The analysis is then extended by considering a fully coupled hydromechanical formulation and a critical state constitutive model for cemented soils; by simulating conventional laboratory tests on the soil that has entered the tube we can quantify sampling disturbance in terms of geotechnical design parameters (e.g. undrained shear strength and yield stress). The possibilities offered by numerical modelling for site characterization are far from being fully exploited. It is envisaged that in the future site-specific numerical analyses will become available, enabling a more comprehensive understanding of the subsurface conditions.
Abstract
With the advancement of computational geomechanics over the past decades, most of the activities typical of site characterization, such as in situ testing or sampling, can [...]
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PLENARY LECTURE - Treatment of uncertainties in site characterization in second-generation eurocode 7
J. Estaire, T. Schweckendiek

ISC2024.

Abstract
The purpose of this paper is to introduce the geotechnical engineering community to the treatment of uncertainties in site characterization within the framework of the second-generation Eurocodes. To do so, the main uncertainties related to the Ground Model, the ground properties and the groundwater levels are described before discussion of the statistical and modelling involved. This paper also explains the determination of “representative values” of ground properties within the framework of the Second-Generation Eurocode 7, either selecting the value based on engineering judgment and comparable experience, being in this case termed a “nominal value”; or evaluating the value by statistical methods, being in this case termed a “characteristic value”. Additionally, since 2nd-Gen Eurocode 7 allows using reliability-based methods for the verification of limit states, the paper gives some guidance for choosing probability distribution types, and for assessment their parameters like the mean and standard deviation. Finally, two examples are provided to show how to deal with the new elements involved with uncertainty treatment in terms of statistical analysis and probabilistic modelling
Abstract
The purpose of this paper is to introduce the geotechnical engineering community to the treatment of uncertainties in site characterization within the framework of the second-generation [...]
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PLENARY LECTURE - Recent advancements in data-driven site characterization
J. Ching*, K. Phoon

ISC2024.

Abstract
This paper reviews some recent advancements that address the challenges faced by the broad application area of datadriven site characterization (DDSC). The challenges include the ugly-data challenge, site-recognition challenge, and stratification challenge. The ugly-data challenge is about the MUSIC-3X attributes of the site investigation data, where MUSIC-3X stands for multivariate, uncertain and unique, sparse, incomplete, possibly corrupted, and 3D spatial variability (3X). The site-recognition challenge is about the site-uniqueness feature of the site investigation data. The stratification challenge is about the task of layer delineation in soil profiling. In recent years, some studies have been conducted to address these challenges with an encouraging degree of success, which are briefly reviewed in this paper. However, there are still unresolved issues yet to be addressed, which are briefly summarized in this paper as well.
Abstract
This paper reviews some recent advancements that address the challenges faced by the broad application area of datadriven site characterization (DDSC). The challenges include [...]
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PLENARY LECTURE - 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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PLENARY LECTURE - Passive seismic methods for site characterization
C. Cornou*

ISC2024.

Abstract
Site characterization methods to extract the shear-wave velocity (Vs) structure over the first few tens to few hundred of meters or the soil’s resonance frequency using seismic noise recordings have become widespread over the last 40 years. Being cost-effective and easy to implement, especially in urban environment, passive seismic methods have been shown reliable to retrieve the soil resonance frequency and the Vs profile of near-surface geological layers. International efforts over the last 20 years have outlined the capabilities and limitations of passive seismic methods and lead to a series of good-of-practice, state-of-the-art and recommendations on data acquisition and processing. Recent methodological developments using three-component single-station and three-component array methods are promising approaches to better constrain Vs profiles. Also, the very high spatial and temporal resolution offered by the Distributed Acoustic Sensing (DAS) makes this emerging technology one with very high potential for near-surface site characterization, especially in urban environment.
Abstract
Site characterization methods to extract the shear-wave velocity (Vs) structure over the first few tens to few hundred of meters or the soil’s resonance frequency using [...]
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PLENARY LECTURE - Machine learning tools for the treatment of offshore site investigations
B. Stuyts*

ISC2024.

Abstract
During geotechnical and geophysical site characterisation for large infrastructure projects, significant data volumes are being collected which need to be processed and interpreted. Due to the limited budgets available for site characterisation and the various sources of uncertainty, the interpretation relies on a combination of data from various sources (e.g. in-situ and laboratory tests), the use of parameter correlations from the literature and expert judgement. In recent years, modern data science techniques have become increasingly accessible to practicing engineers and researchers and they offer the possibility to improve several aspects of the site characterisation and parameter selection process. Machine learning models can be trained on high-quality datasets and expert judgement can also be internalised in the model formulations. In this contribution, the role of data science and machine learning for geotechnical site characterisation is discussed based on several example applications using datasets from offshore wind farm projects. The role of data coverage and data quality is discussed as well as the role of geophysical data for interpolating geotechnical point measurements in a quantitative way. Supervised and unsupervised machine learning techniques are explained and illustrated on the provided datasets. Finally, a perspective is given on the role of the emerging Large Language Models (LLM) for geotechnical site characterisation applications.
Abstract
During geotechnical and geophysical site characterisation for large infrastructure projects, significant data volumes are being collected which need to be processed and interpreted. [...]
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PLENARY LECTURE - Bio-inspired site characterization - towards soundings with lightweight equipment
A. Martinez*, Y. Chen, R. Anilkumar

ISC2024.

Abstract
Equipment used for site investigation activities like drill rigs are typically large and heavy to provide sufficient reaction mass to overcome the soil’s penetration resistance. The need for large and heavy equipment creates challenges for performing site investigations at sites with limited accessibility, such as urban centres, vegetated areas, locations with height restrictions and surficial soft soils, and steep slopes. Also, mobilization of large equipment to the project site is responsible for a significant portion of the carbon footprint of site investigations. Successful development of selfburrowing technology can have enormous implications for geotechnical site investigation, ranging from performance of in-situ tests to installation of instrumentation without the need of heavy equipment. During the last decade there has been an acceleration of research in the field of bio-inspired geotechnics, whose premise is that certain animals and plants have developed efficient strategies to interact with geomaterials in ways that are analogous to those in geotechnical engineering. This paper provides a synthesis of advances in bio-inspired site investigation related to the (i) reduction of penetration resistance by means of modifying the tip shape, expanding a shaft section near the probe tip, applying motions to the tip like rotation and oscillation, and injecting fluids and (ii) generation of reaction forces with temporary anchors that enable self-burrowing. Examples of prototypes that have been tested experimentally are highlighted. However, there are important research gaps associated with testing in a broader range of conditions, interpretation of results, and development of hardware that need to be addressed to develop field-ready equipment that can provide useful data for geotechnical design.
Abstract
Equipment used for site investigation activities like drill rigs are typically large and heavy to provide sufficient reaction mass to overcome the soil’s penetration resistance. [...]
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Impact of evolving fabric anisotropy on CPT simulations for subsurface characterization
S. Moshfeghi, M. Taiebat*, A. Lizcano

ISC2024.

Abstract
In geotechnical site characterization, Cone Penetration Testing (CPT) is a fundamental method for evaluating subsurface conditions of granular materials such as sands, silts, and non-plastic tailings. This study advances CPT simulations by incorporating the fabric anisotropy variable A into the SANISAND-F model and utilizing the Material Point Method (MPM), with a specific focus on the role of evolving fabric within an anisotropic critical state framework. The objective is to deepen the understanding of how the evolving fabric of soils influences macroscopic site characterization outcomes. Through carefully controlled initial conditions, including void ratio and confining pressure, the study aims to demonstrate the impact of fabric anisotropy on CPT resistance measurements. Assessment of the evolution of material state based on the key constitutive ingredient of the model allows for explaining the reason behind the respective values of cone tip resistance observed from the CPT simulations, considering fabric anisotropy and the anisotropic critical state framework. This approach enhances the modeling of this site characterization method, providing a more comprehensive framework for interpreting soil mechanical behavior and enhancing predictive modeling capabilities
Abstract
In geotechnical site characterization, Cone Penetration Testing (CPT) is a fundamental method for evaluating subsurface conditions of granular materials such as sands, silts, [...]
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Use of the Pocket G-PFEM to Predict Changes in Soil State
J. Carneiro*, M. Junior, A. Faria, G. Pinto

ISC2024.

Abstract
Simulating the CPTu response to changes in the current soil state allows geotechnical engineers to evaluate different scenarios and better predict the structure’s performance. Developed by the Universitat Politècnica de Catalunya, Centre Internacional de Mètodes Numèrics en Enginyeria and TU Graz, the Pocket G-PFEM is a numerical tool that simulates the CPTu in a homogeneous soil layer, adopting an updated Lagrangian description. Two types of cones can be simulated: i) the smooth cone, without lateral friction in the interface cone/soil, and ii) the rough cone, with lateral friction. The Clay and Sand Model is adopted as the soil constitutive model. This study assessed the software response to changes in the overconsolidation ratio (OCR) and compressibility parameters (λ and κ) in both cone modules. The rough cone analyses resulted in higher qt and u1 than the smooth cone, but no significant change was observed in u2 and u3. The Pocket GPFEM could partially reproduce the expected behaviours from the literature, but u2 and u3 did not decrease significantly for high OCRs, and the rough cone could not adequately simulate the fs. Following the literature, qt was mainly sensitive to λ for the OCR = 1 and to κ for the OCR = 2, but an unexpected behaviour was observed for the OCR = 8 when changing λ and κ. The results show Pocket G-PFEM’s limitation in reproducing qt, fs, and u for high OCRs. It might be related to the adopted parameters, and different sets should be evaluated.
Abstract
Simulating the CPTu response to changes in the current soil state allows geotechnical engineers to evaluate different scenarios and better predict the structure’s performance. [...]
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Types of Shearing and Anisotropy in Undrained CPTu
D. Durán*, L. Monforte, M. Arroyo, A. Gens

ISC2024.

Abstract
Most natural clays acquire an anisotropic fabric upon deposition. This anisotropic fabric induces differences in the soil mechanical responses, for instance in the undrained shear strength observed in the laboratory. It is unclear how much of that anisotropy is reflected on the responses measured by the cone penetration test. In this work, we use GPFEM to numerically simulate cone penetration tests (CPTu) in undrained, anisotropic clays. The constitutive response is represented by S-CLAY1, a critical state, anisotropic model. Full details of the representative stress path during CPTu insertion are provided. Preliminary numerical results suggest that even a large amount of anisotropy, as described by the model, will have a very small effect on the cone responses. The numerical simulation results also show that the prevailing stress path has strong similitudes with that found during anisotropically-consolidated undrained compression triaxial test.
Abstract
Most natural clays acquire an anisotropic fabric upon deposition. This anisotropic fabric induces differences in the soil mechanical responses, for instance in the undrained [...]
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Analysis of Video Images obtained during Cone Penetration Testing
G. Verbeek*, O. Khomiak, W. Bond

ISC2024.

Abstract
One of the ways to enhance the efficiency of the cone penetration testing process is to mount modules behind the cone. In this way the test will not only generate the standard Cone Penetration Testing (CPT) data (i.e., cone tip resistance, sleeve friction, and dynamic pore water pressure), but also the data obtained by the module pushed into the soil together with the cone. While for certain modules it is common practice to analyze the acquired data extensively (e.g., the seismic module) for other modules this is not necessarily the case. A good example of the latter is the video module, which has been available for several decades. When this module is deployed with visible light, the analysis is typically limited to viewing the recording and adding observation notes. During the recent TRIM4 research project the video module was deployed and subsequently attempts were made to identify the soil type through an automatic analysis of the video images and to characterize and to determine the grain size distribution using the video images. This approach is highly correlated with the soil behavior type index, commonly used in the analysis of CPT data, and at the same time mitigates the effect of the CPT data reflecting changes in soil strength behavior before a layer is actually penetrated by the cone. In this paper the authors will describe the use of the video cone in very general terms, but focus on this analysis methodology in detail
Abstract
One of the ways to enhance the efficiency of the cone penetration testing process is to mount modules behind the cone. In this way the test will not only generate the standard [...]
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Interpretation of cone pressuremeter tests to estimate the strain dependent stiffness and strength of sensitive lacustrine clay
J. Schorr*, R. Cudmani, S. Vogt

ISC2024.

Abstract
Field and laboratory testing was carried out for the construction of a 100 m long cable stayed bridge situated in the foothills of the Alps in the south of Germany, a region dominated by deep post-glacial, fine-grained sediments. Due to the sensitivity and associated challenges with retrieving undisturbed soil samples in situ tests and their evaluation proved to be essential for the geotechnical design of the bridge foundation. This contribution focuses on the analytical and numerical interpretation of Cone Pressuremeter Tests (CPM). The non-linear ðº-ð¾ relationship and undrained shear strength (using both the limit pressure and reverse plasticity contraction analysis) were determined analytically. Numerical investigations were carried out as verification using both the Finite Element method (FEM) using both 1D (cavity expansion) and 2D simulations (where the penetration of the probe was modelled) as well as using the Finite Difference (FD) method. 2D simulations demonstrated that the assumption of the cylindrical cavity expansion is appropriate for modelling the CPM tests. The interpreted undrained shear strength showed good agreement with other field tests, including CPTu, vane shear (FVT) and seismic cone penetration (SCPT) tests, as well as with the results of laboratory tests on disturbed samples. CPM tests with strain rate jumps were conducted during pressuremeter expansion, wherewith it was possible to quantify the viscous response of the soil. Based on the holistic interpretation of the field and laboratory results involving both numerical simulations and analytical methods the parameters for the material model Viscohypoplasticity were calibrated.
Abstract
Field and laboratory testing was carried out for the construction of a 100 m long cable stayed bridge situated in the foothills of the Alps in the south of Germany, a region [...]
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Plant Root Circumnutation-Inspired Penetration in Sand and Clay
R. Anilkumar*, A. Martínez

ISC2024.

Abstract
Site investigation (SI) and subsurface exploration are vital for characterizing soil properties. However, a common challenge is the lack of sufficient reaction force to penetrate through stiff crusts or deep layers, leading to refusal. To address this issue, rigs typically have large sizes that can make mobility and accessibility challenging and increase the carbon footprint of SI activities. This paper experimentally investigates a plant root-inspired strategy called circumnutation-inspired motion (CIM) to reduce the vertical penetration forces (ð¹ð§) in comparison to quasi-static penetration used for example for Cone Penetration Testing (CPT). The CIM probes have a bent tip end and are rotated at a constant angular velocity (ð) while they are advanced at a constant vertical velocity (ð£) in uniform specimens of clay and sand. ð¹ð§ for both soils decay exponentially by factors as high as 10 with increasing relative velocity, defined as the ratio of the tangential to the vertical velocity of the probe tip (ðð/ð£). Torques for both soils increase with initial increases in ðð/ð£ which stabilize at higher velocities. While the cumulative total work, calculated for both clay and sand from the measured forces and torques, increases less than 25% for initial increases in ðð/ð£ between 0 and 0.3ð, the ð¹ð§ can be reduced by around 50%. Thus, CIM penetration can produce significant reductions in ð¹ð§ in comparison to CPTs while limiting the additional energy consumed. CIM could be implemented to perform site investigation activities, such as obtaining samples or installing sensors, using smaller-sized, light-weight rigs
Abstract
Site investigation (SI) and subsurface exploration are vital for characterizing soil properties. However, a common challenge is the lack of sufficient reaction force to penetrate [...]
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G-PFEM-aided Derivation of Undrained Shear Strength of Organic Clays from CPT Data
A. Halleux, K. Boschi*, L. Flessati, C. Jommi

ISC2024.

Abstract
Accurate evaluation of undrained shear strength of soils is crucial in geotechnical design and assessment. In the practice, undrained shear strength is obtained most frequently from CPT data, dividing the net cone tip resistance by a cone factor, ð . For organic soils, values between 8.6 and 15.3 are reported, depending on the stress history. The cone factor can be conditioned to the results of laboratory tests, although uncertainties remain on the variety of stress paths followed by the soil elements around the tip of the cone, compared to the ones tested in the laboratory. Non-uniqueness in the definition of the cone factor may lead to either unsafe or over-conservative choices, partly undermining both the reliability and the sustainability of the design. This contribution analyses numerically the inversion technique used to determine the undrained shear strength of organic clays, exploiting data from an extensive in situ and laboratory investigation. The adopted constitutive model was calibrated on the results of laboratory tests. Cone penetration tests were simulated performing coupled hydro-mechanical numerical analyses via G-PFEM, developed in the last decade at CIMNE-UPC. The role played by initial stress state and previous stress history upon stress distribution at failure, cone factor and sleeve friction is discussed. The numerical results suggest how the sleeve friction could be used to condition the cone factor depending on the over-consolidation ratio and demonstrate how combining the different available CPT readings with the aid of numerical results may reduce the uncertainty in the estimation of undrained shear strength.
Abstract
Accurate evaluation of undrained shear strength of soils is crucial in geotechnical design and assessment. In the practice, undrained shear strength is obtained most frequently [...]
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A numerical analysis of CPT-based tip resistance prediction during pile installation in clays
S. zhou*, W. Zhang, A. Osman

ISC2024.

Abstract
Accurately predicting the installation resistance of offshore piles is important for their design and application. The cone penetration test (CPT) is the most widely used in situ sounding tests for pile drivability analysis and capacity prediction. While there are established empirical correlation methods to connect CPT data with pile installation resistance, the underlying mechanisms behind these correlations have yet to be fully understood. This study performs a numerical analysis to reveal such mechanisms and improve the correlations. The pile installation and cone penetration processes are modelled using a large-deformation finite-element method. For all analyses, a smooth cone and a smooth pile are simulated to quantify the relationship of tip resistance between the pile and CPT. The mechanisms of the two analogous penetration processes are visualized and compared through numerical modelling. As the cone advances, it pushes the soil at the cone tip into the far field. During the pile penetration process, soil heaving can be observed with the soil surface inside the pile moving above the mudline. The soil failure is localized at a small zone around the pile tip. The penetration resistances of pile are correlated to CPT data with the aid of numerical modelling and compared to existing CPT-based design guidelines. A discussion on the pile tip resistance correlated with cone tip resistance is included, and the value of the empirical coefficient for tip resistance kp is obtained.
Abstract
Accurately predicting the installation resistance of offshore piles is important for their design and application. The cone penetration test (CPT) is the most widely used [...]
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Prediction of state parameter based on CPT MPM simulations in sandy soils
M. Martinelli*, G. Remmerswaal

ISC2024.

Abstract
Cone penetration tests (CPTs) can provide quantitative information about the mechanical state of sandy soils. In the current state of the art, the soil state is derived from the cone resistance, which is estimated from the cavity expansion solution and a calibrated scaling equation. Recently, Martinelli and Pisano (2022) showed that MPM simulations of CPTs provide accurate values of the cone resistance in sandy soils when using the critical state NorSand model. This paper adopts this framework to develop a predictive equation for cone resistance as a function of the NorSand parameters and the state parameter of the soil. This formula is straightforward to implement, and it can be adopted by researchers and practitioners to assess soil state in a soil deposits.
Abstract
Cone penetration tests (CPTs) can provide quantitative information about the mechanical state of sandy soils. In the current state of the art, the soil state is derived from [...]
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Numerical Study of Cone Penetration in Calcareous Sands: Investigating Cone Tip Resistance Correction Factors for Crushable Soils
S. Hyder*, D. Moug

ISC2024.

Abstract
The cone penetration test (CPT) is used to characterize the behaviour and properties of soils, including the cyclic strength against earthquake liquefaction triggering. The cone tip resistance relates to cyclic strength through relative density, where relative density is closely related to both cone tip resistance and liquefaction susceptibility. Currently, published methods of estimating liquefaction potential (i.e., cyclic resistance ratio) are based on silica sands and do not properly characterize calcareous sands. The measured cone tip resistance in calcareous sands is lower than in silica sands at the same relative density; this difference is generally attributed to the higher compressibility of calcareous sands due to particle crushing during cone penetration. Consequently, application of CPT-based liquefaction triggering evaluations in calcareous sands result in over-conservative analysis. To avoid over-conservative analysis, projects may develop site-specific correction factors to adjust the cone tip resistance in calcareous sand to the equivalent value in silica sand at the equivalent relative density. This study aims to investigate cone penetration in calcareous sands compared to silica sands by examining the roles of soil compressibility and other fundamental soil parameters. The study is performed with a direct axisymmetric penetration model and the MIT-S1 constitutive model calibrated against published mechanical behaviour for a calcareous sand; the simulated cone penetration results are compared with simulated cone penetration in Ottawa F-65 sand. Compressibility of the calibrations is adjusted to explore the role of compressibility on cone tip resistance. The numerical results show that differences in compressibility only partially account for differences in cone tip resistance between calcareous and silica sands at the same initial state. However, the results support that critical state line position does strongly relate to differences in cone tip resistance between the two soil types. The study results provide a basis to investigate differences in critical state line position as a basis for site-specific cone tip resistance correction factors for calcareous soils.
Abstract
The cone penetration test (CPT) is used to characterize the behaviour and properties of soils, including the cyclic strength against earthquake liquefaction triggering. The [...]
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On the Determination of Soil Deformation Modulus by Means of a Penetrometer
S. Volcy*, C. Dano, L. Sibille, B. Chareyre, H. Hosseini-Sadrabadi

ISC2024.

Abstract
Classical Cone Penetration Test (CPT) or CPTu (when water pore pressure is also measured) can provide so far only strength parameters of soils, specifically the tip resistance and the lateral friction. This article presents the numerical simulation in a (virtual) calibration chamber, using the Discrete Element Method (DEM), of a CPT-based test proposed in the quest for possibilities to determine soil deformability parameters as well. It is a non-standard test characterized by force-controlled cycles applied to the penetrometer tip that is movable independently of the penetrometer body. Very small irreversible displacements of the tip are observed over the first cycles whose amplitudes span a region of low fractions of the tip resistance, that is subsequently assimilated to a pseudo-elastic domain within which, deformation moduli can be derived from the slopes of the force-displacement curve properly interpreted. Results also reveal a loading level beyond which, these slopes and the corresponding deformation moduli, significantly decrease while the irreversible displacements of the tip increase substantially.
Abstract
Classical Cone Penetration Test (CPT) or CPTu (when water pore pressure is also measured) can provide so far only strength parameters of soils, specifically the tip resistance [...]
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Experimental and Numerical Investigations of CPT End Resistance at Variable Penetration Rates in Mixed Soils
A. Arafianto*, Y. Tian, B. Lehane, Y. Suzuki, D. Reid

ISC2024.

Abstract
This paper investigated cone penetration test end resistance under various drainage conditions in mixed soils through numerical simulations and piezocone experiments in laboratory testing chambers. The soil samples used in the laboratory tests contained various proportions of kaolin, silt, and sand. The piezocone tests were performed using a 10 mm diameter cone in consolidated soil samples. The measured variations of cone resistance and pore pressure at cone velocities varying from 0.005 mm/s to 30 mm/s are presented, which covered the full range from drained to undrained conditions. The cone resistance was evaluated using the spherical cavity expansion limit pressure predicted in Finite Element (FE) analyses that employed the NorSand (NS) constitutive model. The experimental and numerical findings allow assessment of the suitability of the normalised velocity (V) term, proposed by others, to unify cone resistances measured at variable rates.
Abstract
This paper investigated cone penetration test end resistance under various drainage conditions in mixed soils through numerical simulations and piezocone experiments in laboratory [...]
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Numerical Simulations of Cone Penetration Response via Accounting for State-Dependence and Full-Strain-Range Non-Linearity of Sand
Z. Shi*, S. Tong, M. Huang, J. Yu, B. Wang, C. Sun

ISC2024.

Abstract
The penetration response of CPT is not only related to the stress and density states of sand but also influenced by the nonlinear stress-strain relations of soils from very small (10-5) to relatively large (10-1) strain levels. Appropriate considerations of the above key soil behaviours can be crucial for accurate numerical simulations of CPT response. For this purpose, an intergranular strain (IGS)-based elastic model is introduced into a critical-state-based, state-dependent plasticity model to capture the state-dependence and full-strain-range non-linearity behaviour of sand. A numerical model of the CPT penetration process is then established by combining the aforementioned constitutive model and the arbitrary Lagrangian-Eulerian (ALE) large deformation finite element technique. The latter is adopted to handle the problems of large deformations of soil and mesh distortion. Then the computed response of CPT is compared against centrifuge test observations, and the numerical model is utilized to analyse the influences of the full-strain-range non-linearity behaviour of sand on the penetration response of CPT. The results indicate that the non-linear stress-strain relations at small strains can have noticeable impacts on the tip resistance of CPT, in particular for loose sand, while having a relatively small influence on the penetration depth required to reach a steady-state penetration resistance. The above influences might be attributed to a rapid decay of soil strains with the distance from the cone tip, and consequently high stiffness and strong constraints effects of far-field soils on core soils adjacent to the cone tip
Abstract
The penetration response of CPT is not only related to the stress and density states of sand but also influenced by the nonlinear stress-strain relations of soils from very [...]
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Inherent and CPTu-measured Scale of Fluctuation of Undrained Geomaterials: a Numerical Perspective
L. Monforte*, S. Collico

ISC2024.

Abstract
The vertical scale of fluctuation of soil parameters is often indirectly estimated through Cone Penetration Testing (CPTu) as the test provides nearly continuous and repeatable data. However, the variability quantified from CPTu might not be representative of a soil parameter intra-site variability, but rather the effect of the variability of soil measured through its response to the cone probe. The objective of this work -of an openly prospective nature- is to examine how the vertical inherent spatial variability of clay-like insensitive geomaterials propagates to the cone tip and friction sleeve resistance by means of numerical modelling. A total stress analysis is presented, in which the undrained shear strength is described according to random field theory. Numerical results show that the scale of fluctuation of the tip resistance and friction sleeve resistance is greater than the one assumed for undrained shear strength.
Abstract
The vertical scale of fluctuation of soil parameters is often indirectly estimated through Cone Penetration Testing (CPTu) as the test provides nearly continuous and repeatable [...]
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A DEM Study on the Effect of Chamber Boundary on CPT Calibration Chamber Tests
A. Sadrekarimi*, S. Hashemi

ISC2024.

Abstract
Laboratory-scale cone penetration tests are often carried out to calibrate the response of cone penetration, and in particular cone tip resistance to soil characteristics. However, because of the limited sample size, sample boundaries can often affect the measured cone resistance in laboratory tests. This paper presents numerical simulations using the discrete element method (DEM) to study the effect of boundary condition on cone penetration calibration chamber tests. Numerical simulations were performed under flexible (BC1) and laterally-constrained (BC3) boundary conditions on K0consolidated models at different relative densities and vertical stresses. Additional models were simulated with periodic boundaries (BC5) to model the free-field condition. To track the radial stress variations in different sections of the chamber, scattered representative volume elements (RVE) were embedded in the models. Particle displacements and contact force chains were examined to determine the relation between microscopic variables and macroscopic response of the specimens subjected to cone penetration under different boundary conditions. Larger cone resistances were obtained under BC3 condition than those in BC1 condition. For the chamber-to-cone diameter ratio of 25 adopted in this study, the influence of the lateral boundary was found to be negligible in loose to medium-dense assemblies, while the effect of chamber boundary amplified in dense to very dense samples with increasing relative density and reduced with increasing vertical stress. This was attributed to the higher radial stress induced along the cone penetration path in laterally-constraint BC3 models. Based on these findings, a correction factor is proposed to better estimate free-field penetration resistance from calibration chamber experiments.
Abstract
Laboratory-scale cone penetration tests are often carried out to calibrate the response of cone penetration, and in particular cone tip resistance to soil characteristics. [...]
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The evolution of Menard pressuremeter cavity preparation in France
B. Hamidi, S. Varaksin*

ISC2024.

Abstract
Since Louis Ménard invented his first pressuremeter prototype in 1954, the pressuremeter and its placement techniques into the ground have gone through numerous advancements. In this paper, the authors review the cavity preparation developments in France from the early days of developing the pressuremeter to contemporary times. Pressuremeter probes were initially installed using hand augers, which was quite time consuming and cumbersome. Soon after, drilling was mechanized using drilling rigs with various abilities and capacities in the form of rotary and percussion drilling. Specific techniques such as STAF, RotoSTAF, and similar devices have now been developed to create holes with minimum disturbance in the ground.
Abstract
Since Louis Ménard invented his first pressuremeter prototype in 1954, the pressuremeter and its placement techniques into the ground have gone through numerous advancements. [...]
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Subsurface Characterization of Coastal Deposits using Measurement While Drilling
B. Souza, J. Regan, J. Benoît*, A. Carr, K. Pelham, C. Buerkle

ISC2024.

Abstract
Measurement While Drilling (MWD) is a promising in situ test method that has gained increasing popularity in recent years. MWD can continuously characterize the subsurface while drilling any type of borehole in soil or rock without interfering with normal drilling operations. The latest MWD equipment gathers real-time data on numerous parameters that capture all aspects of the drilling process (e.g., depth, down thrust, rotation, torque, mud flow, and mud pressure). This paper summarizes MWD assessments performed in the coastal deposits of New Hampshire, USA. Profiles of individual and combined drilling parameters were used to differentiate between different soil layers and characterize subsurface conditions in complement with conventional, standardized geotechnical testing (e.g., SPT, CPTU) performed at adjacent boreholes. The results from this experimental campaign demonstrate the applicability of MWD systems to evaluate a broad range of geological conditions, from granular soils with erratic boulders to sensitive clays.
Abstract
Measurement While Drilling (MWD) is a promising in situ test method that has gained increasing popularity in recent years. MWD can continuously characterize the subsurface [...]
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Using Drilling Data to Derive Geotechnical Properties of Variably Cemented Materials
S. Sharma*, J. Rice, P. Suzuki, A. Bertrand

ISC2024.

Abstract
Geotechnical site characterisation of variably cemented material is often challenging due to lack of data. Drilling data is routinely measured as a part of standard geotechnical site investigation and can provide an alternative method to derive continuous ground profiles with depth. This paper examines the use of drilling data for site characterisation purpose. Based on the drilling data obtained from an offshore windfarm project site, where variably cemented materials were found, it is shown that the borehole specific energy calculated using the drilling data reasonably captures the variation in material types with depth. Also, the results show that borehole specific energy can be correlated with the laboratory test data in a similar manner to cone penetration test. Based on the results obtained from different locations covering a range of material types and in-situ state conditions, generalised relationships between different geotechnical parameters and borehole specific energy are presented. An example of how the generalised relationships developed using borehole specific energy can be used to derive design profiles for a selected site is also shown. The data and interpretation approach presented in this paper provide a useful guide for how the drilling data can be used to assess the continuous ground profile for variably cemented sites where only limited or no in-situ test and intermittent sampling data are available.
Abstract
Geotechnical site characterisation of variably cemented material is often challenging due to lack of data. Drilling data is routinely measured as a part of standard geotechnical [...]
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Offshore rock investigations by a remotely operated submersible drilling rig with continuous drilling recording
A. Deu*, M. Pérez, R. del Castillo, M. Devincenzi

ISC2024.

Abstract
The submersible drilling rig presented in this paper was designed and constructed with the aim to allow conducting soil or rock characterization in offshore investigations in shallow water projects when short target penetrations are required. The system is instrumented with sensing elements allowing the full control of the operation in real-time for three different purposes: (i) positioning, (ii) continuous drilling parameters (MWD, measuring while drilling) and (iii) visual inspection. The suitability in sandy and silty soils was reported by Romero et al. (2012). The system is outstanding as an interesting alternative to traditional methodologies for rock investigations in relative shallow water projects where the knowledge of the first metres of rock profile is critical (e.g., pipelines, submarine interconnections, dredging, foundations). Some benefits of the system are presented in this paper, especially in ground models composed of a rock layer underneath a soil deposit or by rocks with variable strength with depth.
Abstract
The submersible drilling rig presented in this paper was designed and constructed with the aim to allow conducting soil or rock characterization in offshore investigations [...]
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Comparison of Direct and Indirect MWD Measurements
C. Caplane, M. Rispal, G. de Oliveira Souza*, M. Peronne, P. Reiffsteck

ISC2024.

Abstract
Drilling boreholes for geotechnical purposes such as sampling and in situ tests is usually performed with the aid of drilling machines. In France, typically, the machine’s drilling parameters such as applied torque and thrust are monitored in realtime and registered so that information about the subsoil’s structure can be acquired. As these machines tend to use hydraulic systems, the oil pressures fed into each motor and actuator are the parameters commonly monitored. Recently, a new type of sensor and its application in geotechnical investigations through the measuring of drilling parameters was presented. This sensor is directly mounted on top of the drill string of a drilling machine and records the actual thrust, torque, and rotation speed transmitted to the drill string and bit. This bypasses the energy losses present in the hydraulic circuit between the machine’s pressure sensors and the hydraulic actuators. This mounting position allows a more accurate measurement of the forces and, furthermore, the effective rotation speed applied to the drill bit. The data is transmitted through a wireless Bluetooth connection enabling real time monitoring. Nevertheless, finding the right balance between a soil’s resistance, the drill rig’s power and the sensor’s optimal measuring range remains a topic for further development. This analysis of several worksites with different soils throughout France contributes to a better understanding of the last generation’s sensor’s precision and application range.
Abstract
Drilling boreholes for geotechnical purposes such as sampling and in situ tests is usually performed with the aid of drilling machines. In France, typically, the machine’s [...]
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Comparative Analysis of Different Methods for Interpreting MWD Profiles
G. de Oliveira Souza*, P. Reiffsteck, F. Szymkiewicz, C. Jacquard, M. Rispal

ISC2024.

Abstract
To determine a robust geotechnical model from measurements of drilling parameters is one of the great desires of geotechnical investigations. Drilling parameters have the advantage of presenting very granular data (data-points every centimetre) much like the CPT. They allow for the identification of soil samples during the drilling process and can traverse all terrain types, from soft clays to hard rocks. However, interpreting each parameter, like penetration rate or thrust, in isolation can be challenging, as these parameters can vary greatly within each soil layer due to natural heterogeneity, the drill rig’s configuration and the noise introduced by the discontinuous interaction between soil and drill bit. Various authors propose using compound parameters such as specific energy, penetration resistance and alteration index alongside cautious filtering allows for a better interpretation, giving physical meaning to the measurements. These compound parameters have been developed from simple correlations, aiming to normalise parameters heavily influenced by drilling conditions or even aiming to evaluate the work or the energy spent in excavating the soil. Beyond that, many authors have devised algorithms to automate or standardize the interpretation of drilling logs by identifying homogenous zones or the probability that a given point belongs to a certain layer. This paper presents a comparison of such methodologies for identifying soil layers based on MWD profiles proposed in the literature. Assessment of the geotechnical structure may be made through different analytic and advanced statistical methods. MWD profiles from worksites throughout France will be used to compare and qualify these methods.
Abstract
To determine a robust geotechnical model from measurements of drilling parameters is one of the great desires of geotechnical investigations. Drilling parameters have the [...]
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Organization and Analysis of Measurement While Drilling (MWD) Data in Montana, USA
D. Barrick*, D. O'Meara, N. Jaynes, C. Link

ISC2024.
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Use of a portable measurement while drilling system for shallow subsurface characterization
B. Souza, F. Pilniere, J. Benoit, M. Bost, P. Reiffsteck*

ISC2024.

Abstract
The Portable Measurement While Drilling (PMWD) equipment designed by CEREMA engineers is an innovative and lightweight tool to perform rapid assessment of shallow subsurface conditions. The equipment consists of sensors mounted on a cordless rotary drill that records depth, downforce, rotation, torque, and time. This paper presents results obtained with the portable MWD under laboratory and field conditions, which were directly compared to soil resistance profiles obtained with a lightweight dynamic cone penetrometer (LDCP – PANDA). Results from 66 PMWD profiles and 87 LDCP profiles demonstrated the potential applicability of the portable MWD in shallow subsurface investigations. A linear correlation between the Somerton Index (SD) and the LDCP tip resistance (qd) was obtained in granular soils under controlled conditions, ranging from sand (SP) to sandy gravel (GP). The obtained relationship was applied to MWD results from a 180-m long, 50-m tall grassy slope in New Hampshire, USA. It was observed that the estimated qd values from drilling parameters have a good correspondence with LDCP results at the same testing locations. Shallow subsurface characterization using MWD can potentially be used for shallow foundations, compaction control, pavement subgrade evaluation, and areas prone to geotechnical hazards not easily accessible through usual exploration methods.
Abstract
The Portable Measurement While Drilling (PMWD) equipment designed by CEREMA engineers is an innovative and lightweight tool to perform rapid assessment of shallow subsurface [...]
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Prediction of Land Surface Subsidence in the U2 Metro Tunnel in Vienna
O. Kichaieva

ISC2024.

Abstract
This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents the algorithm and results analysis of numerical simulation for the step-by-step tunnel construction using the New Austrian Tunnel Method (NATM) in a dense urban environment. The nature and magnitude of subsidence of the earth surface depending on a number of factors involved in the calculation scheme are determined, and all parameters of the stress-strain state of the system "tunnel - ground mass" are obtained. A methodology is proposed for determining reliability by the criterion of additional vertical subsidence of the ground surface which accompanies underground construction. By comparing the results of numerical modelling, empirical calculation and geotechnical monitoring of the metro construction site, it is shown that they correlate well enough with each other. The results of this study can be used to predict the level of the ground settlement during tunnelling works in areas of dense urban development
Abstract
This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents [...]
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The importance of laboratory proficiency testing schemes in assessing and improving uncertainty
C. Wallace, J. Powell*, J. Reynolds

ISC2024.

Abstract
Any site characterisation relies on at least some laboratory tests, and some of those test results (often from basic tests such as Liquid Limit and Plastic Limit) are used in initial design calculations based on correlations. However, the reliability of those correlations is heavily dependent on the uncertainty in the results of those laboratory tests. There is an inter-laboratory proficiency testing scheme that has been running for over fifteen years in the UK, with many worldwide participants. This paper presents a compilation of the scheme’s findings to allow an assessment to be made regarding the reliability of different tests. As an example, repeatability within a single laboratory for the Liquid Limit test by cone penetrometer has been shown to be ± 1 %, but between different laboratories this has risen to ± 6 %. Similar ranges have been found in the Plastic Limits which, taken together with the uncertainties from the Liquid Limits, could give rise to significant concerns over using correlations based on the Plasticity Index. Other examples of results from various test methods are given in this paper and it is argued that much of the uncertainty comes not from the test method itself, but from other factors including basic equipment maintenance, calibration, technician training and competence. It will be seen that laboratory proficiency testing schemes are crucial in highlighting these problems and giving an opportunity to allow better assessment of the quality of both test results and, arguably, the laboratories that produce them.
Abstract
Any site characterisation relies on at least some laboratory tests, and some of those test results (often from basic tests such as Liquid Limit and Plastic Limit) are used [...]
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Modelling the spatial variability of karstified processes in gypsum deposits – the case of a high-speed railway bridge in the Madrid Miocene Basin
J. Pérez-Romero, S. Sandoval*, J. Díaz

ISC2024.

Abstract
The presence of karstification processes in the terrain poses a threat to the safety of the foundations of structures, which in the case of gypsum materials becomes more dangerous due to the rate at which they can progress. This work describes the case of a Spanish high-speed railway bridge whose route runs over a Tertiary gypsum formation belonging to the lower Miocene unit of the Madrid Basin. These are very firm materials in a healthy state, that allow the direct support of shallow foundations, which stand out for their high heterogeneity, with the presence of massive gypsum banks as well as alternating levels of gypsum and clay. However, these materials can be affected by karst processes of dissolution, weathering, and replacement by clays, in which case there is a marked degradation of their mechanical properties, and the eventual local appearance of cavities. In these circumstances, it is necessary to carry out soil improvement treatments, such as compaction grouting, or resort to deep foundations with piles that transmit the loads of the structure to a lower substrate in a non-disturbed state. By its nature, the detection of this type of processes by drilling rotary boreholes is not trivial, and there is often uncertainty associated with its spatial variability. This communication presents the results obtained after the execution of a geotechnical research campaign, consisting of the realization of seismic tomography borehole-profiles under each support of the viaduct, supported by the execution of conventional rotary boreholes. The results of this exploration have made it possible to understand and define the spatial extent of the materials degraded by karstification and the selection of robust foundation typologies that favour the sustainable and resilient nature of the infrastructure.
Abstract
The presence of karstification processes in the terrain poses a threat to the safety of the foundations of structures, which in the case of gypsum materials becomes more dangerous [...]
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A Case Study for Data-driven Soil-layer Delineation
J. Ching*, H. Kamyab, G. Vessia, D. Di Curzio

ISC2024.

Abstract
In the past, soil-layer delineation methods can usually only take a single type of input data, e.g., soil-type data at boreholes. However, this does not fit in the geotechnical engineering practice where multiple types of data are usually available during site investigation (e.g., borehole data and cone penetration test data are both available). This paper adopts a novel data-driven method for soil-layer delineation that accommodates multiple types of site investigation data. The basic idea is to include liquid limit (LL), plasticity index (PI), and fines content (FC) into the soil parameters of analysis. According to the Unified Soil Classification System (USCS), the information of (LL, PI, FC) can be used to determine whether the soil is sand, silt, or clay. As a result, the conditional random field simulation results for (LL, PI, FC) can be used to delineate sand, silt, and clay layers. If extra soil parameters (such as cone penetration test results) are incorporated, the novel method can accommodate multiple types of site investigation data. A real example of the Fucino Basin in Italy is adopted to demonstrate the application of the novel data-driven soil-delineation method.
Abstract
In the past, soil-layer delineation methods can usually only take a single type of input data, e.g., soil-type data at boreholes. However, this does not fit in the geotechnical [...]
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A method to estimate the state parameter from CPTu soundings using Pocket G-PFEM
K. Bernardo*, N. Tasso, M. Sottile, A. Sfriso

ISC2024.

Abstract
The state parameter is the main variable employed for predicting the undrained behaviour of artificial soils such as tailings and hydraulic fills. Current practice involves using screening methods and CPTu data (e.g. Robertson (2010)) or cavity expansion based methods (e.g. Shuttle and Jefferies (2016)). However, these methods have drawbacks: they are based on empirical correlations for clean sands and do not consider the effect of partial drainage. This paper presents a site-specific procedure to determine the state parameter of tailings, inspired in the work by Monforte (2022). The procedure consists of: i) calibrating the CASM constitutive model using triaxial tests for different state parameters; ii) determining the plausible range of hydraulic conductivity based on dissipation tests; and iii) conducting numerical simulations of CPTu tests using the Pocket G-PFEM tool for different combinations of state parameters and hydraulic conductivities. By comparing the results of the simulations with the real CPTu data, a site-specific relationship between the state parameter and the CPTu measurements can be established. To validate the procedure, the method is applied to a real tailings deposit and contrasted against routine screening methods. In the particular case studied in this paper, the method predicts more contractive behaviour than the screening methods. While the method is still in an early stage of development, it looks very promising because it allows for using the raw CPTu data to calibrate a constitutive model, without resourcing to any kind of correlations or empirical transformation models.
Abstract
The state parameter is the main variable employed for predicting the undrained behaviour of artificial soils such as tailings and hydraulic fills. Current practice involves [...]
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On the Probability of Boulder Encounters for Piles Driven in Glacial Till
C. Cannizzaro*, A. Beijer-Lundberg, S. Larsson, J. Spross

ISC2024.

Abstract
Considering that a large part of Sweden is covered by glacial till, which is classified as an unsorted sediment formed by glaciers that can contain fragments of rock known as boulders, driving piles constitutes a substantial economic risk. Piles driven into glacial till may encounter boulders and undergo structural damages leading to premature refusal and to the loss of piles. Even though geotechnical investigations as of today form a solid basis for the design of pile foundations, the unpredictable presence of boulders and their hard resistance to breakage, makes it challenging to penetrate boulders by standard investigation methods. Currently, the only available source of information used by the Swedish construction industry to confirm the existence of boulders is a dynamic penetration test known as soil–rock sounding. Relying on the results from only one testing method may for most projects underestimate the existence of boulders and their potential impact to piles, leading to an unsuitable design of the entire piling system. This paper discusses the benefit in using the input from soil–rock soundings for quantifying the probability of boulder encounters in glacial till based on Poisson point process.
Abstract
Considering that a large part of Sweden is covered by glacial till, which is classified as an unsorted sediment formed by glaciers that can contain fragments of rock known [...]
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An Elaborate Seismic Study of Beirut: Integrating 3D Multidisciplinary Geotechnical Model Definition, Machine Learning Enhancements, and Numerical Simulations
M. Safa*, E. Bertrand, M. Brax, R. Abreu

ISC2024.

Abstract
In seismic hazard assessment, reliance on Vs30 proxies and 1D shear wave velocity profiles often leads to underestimated ground motion. This is particularly evident in areas with complex geological structures, such as Greater Beirut (GB). The metropolis, situated near active seismic faults, experienced significant nearby earthquakes in 551, 1202, and 1837. It is characterized by diverse soil compositions, that vary from sandy terrains to limestone formations, demanding a detailed geotechnical model for seismic hazard studies. Our research developed a comprehensive 3D geotechnical model for GB, integrating data from around 500 boreholes, 700 geophysical measurements, refined DEM, and geological insights. The model delineates variations in bedrock elevation and geological strata, some sites exhibiting sediment depths up to 80 meters. We performed an iterative data analysis by combining the horizontal to vertical spectral ratio method (H/V measurements) with borehole data. This approach enabled us to estimate the average shear wave velocity (Vs-mean) in the sedimentary layer and the depth of the bedrock across the model. To address data gaps in southern GB, we used a Random Forest machine learning model, trained on interpolated points from Kriging in the central model part, ensuring continuous representation of sedimentary units even in data-limited areas. Ongoing work involves seismic simulations predicting ground motion amplification in Beirut. Using a 3D hexahedral mesh generated via Python code, we will conduct full 3D numerical simulations of seismic wave propagation. These simulations aim to provide insights into Beirut's seismic response, contributing to earthquake preparedness and risk mitigation. We will present preliminary results in predicting the seismic motion in Greater Beirut using SPECFEM3D, a spectral-element method software designed for 3D seismic wave propagation simulations.
Abstract
In seismic hazard assessment, reliance on Vs30 proxies and 1D shear wave velocity profiles often leads to underestimated ground motion. This is particularly evident in areas [...]
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Material Subgrade Variability In Site Characterisation
B. Look*

ISC2024.

Abstract
Delineation of areas into a “uniform” harvestable quality material is required for cut and fill earthworks projects. Mixing or inadvertent contamination with onsite high-quality material with adjacent poor quality is unacceptable. Importing material from off-site sources have significant cost associated. Two case studies are presented to highlight the design and contractual interpretation of a “unform” site. The first case study compares when a characteristic design value is used versus the day to day on site requirements to meet these design requirements. The required coefficient of variation (COV) of material parameters is discussed from both a design and construction perspective for section delineation. A major highway road widening had 4 sections as part of the upgrade. The tender documents were based on balanced cut to fill. On site material variability had pockets of good and bad material. Statistical analysis pre and post tender were compared in the contractual dispute which followed. The contractor was obligated to then import material to significant subgrade depths for these sites. To do otherwise would be contra to both the design material requirements specified in the contract documents and the requirements of the Earthworks specifications. The second case study is for a major 13 km rail upgrade to illustrate how the COV can be used in site characterisation and spatial variation at a cutting. The COV values adopted for both design and construction assessment are different as the intent is different. A quality control COV is different for a characteristic design COV.
Abstract
Delineation of areas into a “uniform” harvestable quality material is required for cut and fill earthworks projects. Mixing or inadvertent contamination with onsite high-quality [...]
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Geotechnical characterization using geophysical tests in areas of high geological complexity and landslides for horizontal directional drilling design
C. Buenahora*, P. Salamanca, A. Martínez

ISC2024.

Abstract
In August 2021, landslides occurred on the slope of the Cortinas sector over an area of more than three kilometers, which affected electrical towers, a national vehicle highway, an oil pipeline and a gas pipeline. Currently, these infrastructures have limitations in their operation, generating significant economic losses and therefore, in the case of the gas pipeline, the construction of a HDD of two thousand meters in length at depths of up to one hundred meters is proposed, with the purpose of being able to bypass the zones unstable and restore transportation to normal conditions. The design and construction of said work constitutes a challenge, since the project area has very special geological conditions, since the hillside deposits are very susceptible to failure and there is apparently a stress tensor of an active fault that directly affects the stability of the area. The projected HDD crosses a ravine and a slope with steep topography with difficult access, as well as different layers of sedimentary rock with intercalations, which are folded and highly fractured and saturated with water. These special conditions generated difficulties and opposed the completion of several attempts by other HDDs, but taking into account that this alternative constitutes basically the only solution from a technical point of view, it was necessary to carry out some borehole and multiple seismic geophysical tests and geoelectrical that would allow defining a detailed stratigraphic profile to be able to analyze the constructive feasibility and, in such case, the most appropriate method, as well as the geomechanically characterization of the rocks, since according to the numerical modeling they indicate that the stability of the drilling may be affected due to plasticization at its limits, with detachments of rock fragments and jamming of the tools necessary for its construction.
Abstract
In August 2021, landslides occurred on the slope of the Cortinas sector over an area of more than three kilometers, which affected electrical towers, a national vehicle highway, [...]
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Determination of rock foundation levels for the expansion of the Cañaveral shopping center from geophysical tests and its correlation with direct exploration
C. Buenahora*, F. Castellanos, M. Antonio

ISC2024.

Abstract
The Cañaveral shopping center is located on a low slope formed by recent alluvial deposits of low consistency, supported on sedimentary rock of the Girón formation, which is found at depths that change abruptly between one and twelve meters in short distances, influenced by the presence of a geological fault line and processes of erosion and weathering by subway water currents. Considering that the loads on the foundation are of great magnitude, it is necessary to build about 100 deep caisson foundations to reach the rock. However, performing a borehole on each one of them represented a very high cost and long execution times that would generate discomfort in the operation of the warehouse. Therefore, an alternative was proposed to determine the depth levels of the rock through different geophysical tests of seismic lines and electrical tomography and try to calibrate the results through the correlation of some boreholes. During the execution and data processing phase of the geophysical tests, difficulties were encountered due to the level of environmental noise and the obtaining of the wave records, given the variability of the rock levels and even the effect that in some sectors of the study area the rock is very sub-surface. In conclusion, it was possible to identify the strengths and weaknesses of each of the exploration methods and generate a 3D map of the depths of the rock levels that served as input for the design and budget of the foundations, which were verified by constant supervision during construction and thus be able to determine the error percentages, as well as to present recommendations for future works where it is intended to use this type of techniques
Abstract
The Cañaveral shopping center is located on a low slope formed by recent alluvial deposits of low consistency, supported on sedimentary rock of the Girón formation, which [...]
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Multivariate Gaussian Process for 3D subsurface stratigraphy prediction from CPT and labelled borehole data
O. Zinas, I. Papaioannou, R. Schneider, P. Cuéllar

ISC2024.

Abstract
Quantifying uncertainties in subsurface properties and stratigraphy can lead to better understanding of the ground conditions and enhance the design and assessment of geotechnical structures. Several studies have utilized Cone Penetration Test (CPT) data and employed Bayesian and Machine Learning methods to quantify the geological uncertainty, based on the Robertson’s soil classification charts and the Soil Behaviour Type Index (Ic). The incorporation of borehole data can reduce the stratigraphic uncertainty. Significant challenges can arise, however, mainly due to the intrinsic differences between field and laboratory-based soil classification systems, which can potentially lead to inconsistent soil classification. To this end, this study proposes a multivariate Gaussian Process model that utilizes site-specific data and: i) jointly models multiple categorical (USCS labels) and continuous (Ic) variables, ii) learns a (shared) spatial correlation structure and the betweenoutputs covariance, and iii) produces two types of dependent classification outputs. The results indicate that the integration of geotechnical and geological information into a unified model can provide more reliable predictions of the subsurface stratification, by allowing simultaneous interpretation of USCS and Ic profiles. Importantly, the model demonstrates the potential to integrate multiple variables of different types, aiming to contribute to the development of a methodology for joint modeling of geotechnical, geological and geophysical data.
Abstract
Quantifying uncertainties in subsurface properties and stratigraphy can lead to better understanding of the ground conditions and enhance the design and assessment of geotechnical [...]
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Development of liquefiable zone mapping using semi-empirical methods
B. Berkat*, A. Akhssas

ISC2024.

Abstract
One of the most significant processes in soil dynamics is liquefaction. It is a loss of strength coupled by a quick increase in pore pressure, causing soil particles to break apart for a brief period. There have been several approaches published for calculating the residual or liquefied shear strength of cohesionless soils. This article gives cone penetration test relationships for assessing vulnerability to loss of strength and liquefied shear strength in a variety of soils. Then, based on the results of our studies, we were able to map the liquefiable zones of the Mnasra region, located in the Gharb basin and extending over an area of 4000 km2, which is characterized by two main facies: (i) a predominantly gravelly and/or conglomeratic facies, separated by silt-clay levels (east of the nappe), (ii) a predominantly sandy, sandstone and calcareous facies, separated by silt-clay levels (coastal zone and southern sector on the Maâmora side). IPL calculations predict a spatial-temporal variation in liquefaction at depths ranging from a low probability of liquefaction to a certainty
Abstract
One of the most significant processes in soil dynamics is liquefaction. It is a loss of strength coupled by a quick increase in pore pressure, causing soil particles to break [...]
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A Numerical Study on Effect of Site Conditions on Connection Load in Geosynthetics-Reinforced Soil Wall
A. Kumar*, A. Prashant

ISC2024.

Abstract
Geosynthetics-reinforced soil (GRS) walls have gained immense popularity among other reinforced soil walls. In recent times, case studies have highlighted several GRS walls facing problems such as cracking on the facia, breakage of connection pins in the segmental block, breakage of connection between facia and reinforcement, and relative settlement between facia and backfill, all leading to the serviceability issues or failure of the wall. The existing design methods estimate connection loads using laboratory pull-out tests, which do not incorporate the effect of on-site conditions, such as differential settlement, compaction-induced stresses, and facia geometry, and the stress mobilization in the connection system. This study examines the stress distribution in the facia connection system of segmental reinforced soil walls subjected to site conditions such as inadequate backfill compaction and differential settlement between facia and backfill. A finite element (FE) approach has been adopted to predict the stresses in the reinforcement for the connection loads in the reinforcement-facia connection system subjected to the above-mentioned conditions. The modular block facia, along with geogrid reinforcement connections, was studied, incorporating appropriate geometrical and interface properties (viz. geosynthetics-block interfaces). Based on the study, the obtained variation in the von Mises stresses in the geogrid, embedded in the modular block, due to connection load at the service state was analysed. A comparative analysis of the performance of three different segmental block facia-reinforcement connections was also performed to understand their suitability in a particular site condition
Abstract
Geosynthetics-reinforced soil (GRS) walls have gained immense popularity among other reinforced soil walls. In recent times, case studies have highlighted several GRS walls [...]
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Shear Wave Velocity Derived from Cone Penetration Tests In Clayey Soil Layers
W. Li*, X. Ma, L. Luo, Z. Ouyang

ISC2024.

Abstract
Based on Cone penetration tests (CPT) data, a number of soil’s physical and mechanical parameters can be interpretated, like shear wave velocity, etc. Even though various studies have been conducted and methods are proposed, uncertainties still exist and the applicability of each method needs be further clarified. A case study on the interpretation of CPT results is performed which based on the measured data from an offshore site close to East Sea, China. This paper focus on clayey soil layers and presents an assessment of CPT data interpretation methods for the derivation of clayey soil’s shear wave velocity. It shows that Long’s method proposed in 2010 (C1) and Cai’s method proposed in 2014 (C2) provide better predictions of shear wave velocity. Additionally, values of soil unit weight used in the shear wave velocity derivation can also be interpretated from CPT data since it shows ignorable effect on the interpretated velocity profile.
Abstract
Based on Cone penetration tests (CPT) data, a number of soil’s physical and mechanical parameters can be interpretated, like shear wave velocity, etc. Even though various [...]
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Numerical study of viscous effects during CPTu
L. Hauser*, D. Durán, L. Monforte, M. Arroyo, A. Gens

ISC2024.

Abstract
Variable penetration rates during CPTu may impact cone readings through partial consolidation during penetration but also through viscous soil skeleton behaviour. The latter phenomenon is characteristic of dynamic penetrometers during fast penetration in fine-grained materials where tip resistance increases when the penetration rate increases. In this work, the effect of viscosity on piezocone penetration is investigated based on the numerical simulation of CPTu and triaxial tests using the application G-PFEM and a viscoplastic version of the Clay and Sand Model (CASM). The study highlights that the CPTu results are sensitive to the material parameters controlling viscosity, thus requiring careful calibration in order to obtain realistic CPTu simulations.
Abstract
Variable penetration rates during CPTu may impact cone readings through partial consolidation during penetration but also through viscous soil skeleton behaviour. The latter [...]
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Prediction of Land Surface Subsidence in the U2 Metro Tunnel in Vienna
O. Kichaieva*, D. Adam

ISC2024.

Abstract
This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents the algorithm and results analysis of numerical simulation for the step-by-step tunnel construction using the New Austrian Tunnel Method (NATM) in a dense urban environment. The nature and magnitude of subsidence of the earth surface depending on a number of factors involved in the calculation scheme are determined, and all parameters of the stress-strain state of the system "tunnel - ground mass" are obtained. A methodology is proposed for determining reliability by the criterion of additional vertical subsidence of the ground surface which accompanies underground construction. By comparing the results of numerical modelling, empirical calculation and geotechnical monitoring of the metro construction site, it is shown that they correlate well enough with each other. The results of this study can be used to predict the level of the ground settlement during tunnelling works in areas of dense urban development.
Abstract
This paper discusses the numerical and probabilistic modelling of the tunnel construction concerning some not yet completed sections of the Vienna U2 metro line. It presents [...]
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Availability of artificial neural network for Estimation of Consolidation Properties of Holocene Clays in Osaka Bay
K. Oda*, S. Yamamoto, M. Kondo, T. Inui

ISC2024.

Abstract
In this study, artificial neural network, a popular machine learning technique, was used to estimate the consolidation properties of points where no soil investigations have been conducted. The Holocene clay layer at the construction site of Kobe Airport, a large-scale man-made island in Osaka Bay, was targeted to estimate the consolidation properties. The performance of an estimation model built with artificial neural network depends on the datasets used during the training phase. Therefore, the average of multiple estimation results can be used. Numerical simulations using the estimated consolidation properties can accurately reproduce the settlement behavior owing to reclamation during the construction of Kobe Airport. Artificial neural network can easily and objectively estimate the consolidation characteristics of any point based on the existing soil investigation results.
Abstract
In this study, artificial neural network, a popular machine learning technique, was used to estimate the consolidation properties of points where no soil investigations have [...]
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A Case Study on Quantile and Percentile Regression to Select Design Lines for Complex, Real Work Profiles
J. Valderrama*, M. O'Neill, F. Bransby, P. Watson

ISC2024.

Abstract
Site characterisation necessarily relies on engineering judgement, usually combined with some level of statistics to define characteristic values for design purposes. A suitable method for this task is quantile regression, which allows for the definition of lower, upper, and best-estimate characteristic values. The application of quantile regression to homogeneous profiles is relatively straightforward. Although such sites are common in some areas, there is need for a more comprehensive approach to quantile regression that covers the more general scenario of heterogeneous stratified profiles. This paper takes piezocone penetrometer data from a relatively complex seabed site and demonstrates the streamlined application of quantile regression, highlighting and analysing some of the assumptions and choices behind the approach. The work shows the nuances of the method and suggests workarounds for potential scenarios where its application may be challenging.
Abstract
Site characterisation necessarily relies on engineering judgement, usually combined with some level of statistics to define characteristic values for design purposes. A suitable [...]
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Effect of clay activity and interface surface material on residual undrained interface strength: implications on pipeline-seabed interaction analysis
R. Das*, Z. Westgate, A. Sephoori, S. Garmon

ISC2024.

Abstract
Characterization of the geomechanical behavior of the seabed along a high-pressure high-temperature (HPHT) pipeline route is important for understanding risks from geohazards and thermally induced displacements such as axial walking. Axial resistance to pipeline displacement, from the friction between seabed and the contact surface of the pipe, can be estimated through laboratory tests using interface shear box (ISB) and tilt table. Tests performed by NGI in several developements in Gulf of Mexico, South America, and West Africa revealed significant variation in shear resistance, potentially associated with the type of interface material and surface roughness characteristics. This paper illustrates the effect of clay activity and interface surface material on the residual undrained interface strength estimated from interface shear box tests. Two cohesive soil batch samples with varying activity were tested using two different interface plates (steel and silicon carbide sandpaper) of comparable surface roughness. Each soil batch-interface combination was tested under three different initial effective normal stresses and two different over consolidation ratios (OCRs). Undrained residual interface strength envelopes were developed for each soil batch-interface combination. The results from tests performed on steel interface showed an increase in residual undrained interface strength with plasticy and clay activity whereas a reverse trend was observed in the results of the tests performed using the sandpaper interface. This reinforces the importance of the choice of interface plate material (in addition to surface roughness) for PSI testing program to accurately capture the resistances offered by the seabed to pipe displacement.
Abstract
Characterization of the geomechanical behavior of the seabed along a high-pressure high-temperature (HPHT) pipeline route is important for understanding risks from geohazards [...]
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Uncertainty Estimation on Active Surface-Waves Based Tests
E. Saez*, F. Hernandez, R. Vega, J. Tiznado, R. Gallardo, F. Leyton, G. Montalva, C. Pasten

ISC2024.

Abstract
Geophysical methods based on surface waves have become very popular in recent decades due to their versatility and reduced cost of execution compared to other invasive techniques. Due to space constraints in urban environments, measurements with linear arrays using active and passive techniques are usually combined to reach the exploration depth required by seismic site classification regulations. Although several good practice guidelines have been developed for performing this type of geophysical explorations, one of the remaining major challenges is to relate the results of these explorations to uncertainty metrics. In the case of active tests, there are effects associated with the filtering method used to eliminate the near and far-field effects, as well as other difficulties related to higher Rayleigh-modes or heterogeneities of the site. In this paper, we study the effect of body waves unavoidably induced in active tests on the proper determination of the dispersion curve of a site. For this purpose, active tests are carried out using triaxial geophones to extract from the records the motion effectively corresponding to Rayleigh waves by means of the Normalized Inner Product (NIP) technique. The results show that the effects of body waves are negligible for frequencies above about 8 Hz, but below this value, in the transition zone with ESPAC passive tests, the differences can be more significant. These results are used to introduce uncertainty indicators in this type of explorations
Abstract
Geophysical methods based on surface waves have become very popular in recent decades due to their versatility and reduced cost of execution compared to other invasive techniques. [...]
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Record of long-term field observation of large-scale cutting slope
S. Hijikata*, R. Kuwano, H. Nakamura

ISC2024.

Abstract
This paper describes the interpretation of landslide behavior and verification of the effectiveness of countermeasure works based on the results of long-term field observations at a large-scale cutting site. The site has been subjected to various deformations since its construction due to its unique geological conditions, and has been monitored extensively by GPS surface displacement gauges, borehole inclinometers, anchor load cells, and water level gauges as an important monitoring site even after it was put into service. In the sixth year after the site was opened to public use, we assumed underground slip surfaces based on an interpretation of the observed data, constructed additional countermeasures, and verified the effectiveness of the countermeasures through continuous field observation of intermittent landslide behavior observed in several areas of the slope. As a result, it was confirmed that the displacement had not been settled even five years after the construction of the additional countermeasures and that a new slip surface had emerged, indicating the necessity of improving field observation techniques and data interpretation as well as continuous monitoring of this site
Abstract
This paper describes the interpretation of landslide behavior and verification of the effectiveness of countermeasure works based on the results of long-term field observations [...]
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Quasi-region-specific model uncertainties of simplified liquefaction triggering analysis
J. Wang, J. Ching*, Y. Tu

ISC2024.

Abstract
In earthquake-prone regions, assessing soil liquefaction potential is indispensable for contemporary seismic design. Various procedures for liquefaction triggering analysis have emerged over the past decades. However, most of them are derived from generic liquefaction databases, such that the model uncertainties in liquefaction potential assessments applied to a specific region of concern remain unknown, which poses a challenge for engineers to evaluate the liquefaction risks of target sites. This study aims to propose a hierarchical Bayesian model (HBM) to learn the inter-region characteristics of model uncertainties of the traditional simplified liquefaction potential evaluation methods based on a database containing global case histories of liquefaction categorized into several regions where those triggering events occurred. The learning outcomes can yield the model uncertainty of the target region, and the liquefaction probability at the target site under a given ground motion condition. For an illustration of the proposed model, a case history of liquefaction from a specific region is adopted to construct a quasi-region-specific model uncertainty and evaluate the liquefaction probability in the target soil. The illustration shows that the constructed quasi-region-specific model uncertainty with liquefaction histories in the target region can improve liquefaction occurrence prediction in comparison with the prediction without any histories, which is believed to benefit the engineering practice.
Abstract
In earthquake-prone regions, assessing soil liquefaction potential is indispensable for contemporary seismic design. Various procedures for liquefaction triggering analysis [...]
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Statistical Uncertainty of Cyclic Resistance of Sand under Constant Volume Direct Simple Shear
Y. Sun*, B. Stuyts, W. Haegeman

ISC2024.

Abstract
In the design work of offshore foundations, such as monopiles and gravity platforms, the cyclic resistance of soil plays a critical role in assessing the effect of cyclic loading induced by wind, waves, and rotor dynamics during the operational lifetime. However, the cyclic behaviour of soil is often derived from only a limited number of laboratory tests, which can lead to inaccurate estimates of soil behaviour. Furthermore, this imprecision can affect the parameters selection for the design process. To gain a better understanding of the limitations and uncertainties associated with laboratory experiments, a series of cyclic direct simple shear (cDSS) tests are conducted on marine sand. Four combinations of consolidation stress and void ratio are selected, and a constant volume cDSS test is repeated a substantial number of times for each combination. This dataset captures the measurement uncertainty on the cyclic soil resistance. By analysing the variability of the results, the statistical distributions for the cyclic soil resistance parameters can be determined (e.g. number of cycles to reach a certain shear strain level). The same specimen exhibits slightly different strain-stress relationships due to the inherent variability of sand. Statistical methods are used to describe the cyclic resistance of the sand.
Abstract
In the design work of offshore foundations, such as monopiles and gravity platforms, the cyclic resistance of soil plays a critical role in assessing the effect of cyclic [...]
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Comparative Assessment of the Vertical Scale of Fluctuation of Undrained Shear Strength of Clays From CPT and DMT Testing: a Case Study in Central Italy
M. Uzielli*, A. Galassi, M. Zei

ISC2024.

Abstract
The quantification of the spatial variability of soil properties allows the enhanced engineering modelling, analysis, and design of geotechnical systems. Evolutionary design codes such as Eurocode 7 are awarding spatial variability an increasing central role in geotechnical design. The spatial variability of geotechnical properties is often investigated using a random field approach. Among the defining parameters of a random field is the scale of fluctuation, which describes the extent of significant spatial correlation in a specific spatial direction. The scale of fluctuation can be estimated quantitatively using a variety of methods relying on statistical approaches. The scale of fluctuation is not an inherent property of a soil. Existing studies demonstrate its dependency from numerous factors including the spatial direction, measurement interval, and user-defined modelling options. This paper illustrates the procedures and main results of the comparative estimation of the vertical scale of fluctuation of undrained shear strength of a layer of silty clay from piezocone (CPTU) and dilatometer (DMT) testing at a rural site in the region of Tuscany in central Italy. Vertical scales of fluctuation were calculated using two methods available in the geotechnical literature. Quantitative estimates are compared and analysed critically.
Abstract
The quantification of the spatial variability of soil properties allows the enhanced engineering modelling, analysis, and design of geotechnical systems. Evolutionary design [...]
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Modeling and Characterizing Locally Subsiding Ground for the Analysis and Design of Mat Foundations
D. Coduto*

ISC2024.

Abstract
Mat foundations are often used as a means of protecting buildings and other structures from excessive distortion due to differential settlements in the underlying ground. Once soil bearing capacity concerns have been addressed, the analysis of these foundations becomes a soil-structure interaction problem where the bearing pressure from the mat induces settlement in the underlying ground while localized settlement distorts the mat and redistributes the bearing pressure. An accurate representation of this soil-structure interaction is necessary to facilitate computations of the shear and flexural stresses in the mat and to develop an appropriate structural design. However, modeling and characterizing this system has long been a source of confusion and contention among both geotechnical and structural engineers. The soil response is typically characterized using the modulus of subgrade reaction, ks (also known as the coefficient of subgrade reaction) which describes a certain mechanical soil-structure interaction model known as a Winkler foundation. However, ks is arguably one of the most misunderstood and misapplied parameters in geotechnical practice, and proper assessment of this parameter is more complex and nuanced than might be expected. Further complexities are introduced when locally subsiding ground is present. This is because the Winkler model assumes settlement occurs in the soil only in response to an applied bearing pressure, whereas local subsidence introduces additional settlement (with associated shear and flexural stresses in the mat) which is independent of that caused by the applied structural loads. Methods of modeling and characterizing the subsurface conditions for the purpose of developing design values of ks to be used in mat foundation analysis and design are proposed, then these methods are extended to accommodate sites with locally subsiding ground. These methods are compatible with standard geotechnical assessment techniques as well as standard structural analysis and design software packages.
Abstract
Mat foundations are often used as a means of protecting buildings and other structures from excessive distortion due to differential settlements in the underlying ground. [...]
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Identification of random field for ground stiffness by data assimilation based on surface wave method and sounding tests
S. Nishimura*, Y. Ren, T. Shibata, T. Shuku

ISC2024.

Abstract
The surface wave method (SWM) and the screw weight sounding (SWS) are employed as a geophysical exploration method and a sounding test, respectively to identify the spatial distribution of the stiffness of an earth-fill dam in the present study. The ensemble Kalman filter (EnKF) is used as a data assimilation technique. It can estimate the spatial distribution of the Young’s modulus as the stiffness of an earth-fill dam by assimilating the travel time to the first arrival of the surface waves. By the ensemble data assimilation, the measured data from the SWM is applied to simultaneously estimate the Young's modulus and evaluate the uncertainties. The SWS results are employed as the prior information to generate the initial ensemble through the sequential Gaussian simulation (sGs). Proposed method has been applied to the actual data of the SWM and the SWS measured at an earth-fill dam site. Consequently, it has been clarified the proposed approach could identify the appropriate random field of Young's modulus.
Abstract
The surface wave method (SWM) and the screw weight sounding (SWS) are employed as a geophysical exploration method and a sounding test, respectively to identify the spatial [...]
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Toward probabilistic ground models for time and cost estimation of tunnel projects
J. Spross*, I. Papaioannou, J. Grasmick

ISC2024.

Abstract
The construction time and cost of a rock tunnel project are highly dependent on the rock mass quality and encountered ground behaviour. In most rock tunnel projects, the knowledge about the ground conditions along the tunnel is limited, making it difficult to predict accurately the construction time and cost. The KTH model takes a probabilistic approach to address this problem; however, it does not account for the spatial variability of the ground conditions. This paper investigates an alternative probabilistic ground model to be used within the KTH model that enables accounting for the spatial variability through Markov random field theory. The new ground model employs a parametric approach to describe the properties of the Markov field, hence, enabling the simulation of the ground conditions with limited data, but does not consider the epistemic uncertainty in the model parameters. This will be the addressed in future research.
Abstract
The construction time and cost of a rock tunnel project are highly dependent on the rock mass quality and encountered ground behaviour. In most rock tunnel projects, the knowledge [...]
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Data-Driven Simulation of Multivariate Cross-Correlated Geotechnical Random Fields from Sparse Measurements
Z. Guan, Y. Wang*

ISC2024.

Abstract
It is widely acknowledged that many geotechnical properties are correlated over space and/or time. Consequently, crosscorrelated random fields play a pivotal role in geotechnical reliability analysis for properly modeling both the auto- and cross-correlation structures of correlated geotechnical properties. Existing methods for simulating cross-correlated random fields typically require precise knowledge of random field parameters as input. However, in a typical site investigation program, engineering constraints such as limited time, budget, and space often lead to sparse measurements of geotechnical properties. Estimating reliable random field parameters, particularly the auto-correlation and crosscorrelation structures of a two-dimensional (2D) cross-correlated random field, from such sparse data is a notorious challenge. To address this issue, this study introduces a 2D cross-correlated random field generator that can directly simulate 2D multivariate cross-correlated geotechnical random field samples (RFSs) from sparsely measured data points. This generator leverages the method developed by Guan and Wang (2023), which employs a joint sparse representation to simultaneously exploit auto- and cross-correlation structures of various spatial/temporal quantities directly from sparse measurements. The effectiveness of the proposed generator is demonstrated using real geotechnical properties data. The results demonstrate that RFSs generated using this method from sparse measurements accurately capture the spatial auto- and cross-correlation structures of different geotechnical properties.
Abstract
It is widely acknowledged that many geotechnical properties are correlated over space and/or time. Consequently, crosscorrelated random fields play a pivotal role in geotechnical [...]
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Stratification identification and prediction of missing CPT data by Mixture of Gaussian Processes
M. Durmaz*, A. van den Eijnden, M. Hicks

ISC2024.

Abstract
Stratification identification and spatial interpolation play a fundamental role in geotechnical site characterization. A unified approach is needed to perform these two tasks simultaneously to reduce overall uncertainty in site characterization. This paper explores the applicability of the Mixture of Gaussian Processes (MoGP) to address this gap, with a specific focus on characterizing and completing missing CPT data. The investigation encompasses both synthetic and real-world field CPT datasets and includes a comparison of the MoGP's interpolation accuracy with the use of a single GP for entire datasets. Additionally, the study examines the sensitivity of the model's performance with respect to the number of training data points. Although the interpolation performance of the MoGP model is promising with synthetic data, limitations appear in its application to real-site CPT data.
Abstract
Stratification identification and spatial interpolation play a fundamental role in geotechnical site characterization. A unified approach is needed to perform these two tasks [...]
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SDMT VS profiles in heterogeneous granular soil deposits
F. Totani*, V. Tomei

ISC2024.

Abstract
Many urbanized areas of the Apennines, in Italy, have complex soil stratifications. A typical example is the historical center of L'Aquila and its outskirts, founded on layers of significantly heterogeneity and struck by a strong earthquake in 2009. Under these conditions, shear wave velocity profiles (VS) obtained from in-situ measurements using SDMT techniques allow reliable analyses of local seismic response. In the soil of L'Aquila, the use of SDMT tests in sand-filled boreholes, following the procedure described by Totani et al. (2009), allowed VS to be measured at considerable depths. This article presents the results of local seismic response analyses conducted to characterize the soil foundation of the hospital complex and adjacent university buildings in L’Aquila before their seismic retrofitting. The authors developed a soil model based on the Vs profiles retrieved from the SDMT tests. This approach provided a detailed understanding of the soil seismic behaviour, essential for the proper characterization of seismic action and consequently, the design of seismic interventions. The study emphasises the importance of accurate soil characterisation prior to seismic upgrades especially in deposits where there are multiple shear wave velocity inversions. The seismic demand coming from the Italian Building Code of 2018, based on the so-called soil categories from equivalent velocity of shear wave, was compared to the results of the local seismic response analysis conducted by using the real Vs profiles from SDMT, which are extended to a much greater depths than those generally required by the regulations.
Abstract
Many urbanized areas of the Apennines, in Italy, have complex soil stratifications. A typical example is the historical center of L'Aquila and its outskirts, founded on layers [...]
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Compacted Landfill Quality Based on DMT
A. Penna*, A. Macedo, G. Freitas, L. Melo

ISC2024.

Abstract
For the last 25 years we have been using DMT tests to check the quality of landfill compaction. In several situations of large areas subject to earthmoving, significant pathologies were observed associated with the occurrence of settlements, determined by poor compaction of landfills. These settlements affect the internal floors of buildings, external floors, and sometimes the foundations also. With the intense use of the DMT test as an usual geotechnical investigation practice, it was possible to group the results of these tests, separating them into cases of good, average, and bad behavior. With these systematic observations, it was possible to adapt the traditional graphical representation proposed by Silvano Marchetti and David Crapps, relating the material index "Id" with the dilatometer modulus "Ed", creating regions that represent well-compacted landfills, those with medium compaction and poorly compacted landfills. This system makes it easy to predict the settlement behavior of compacted landfills and represents an appropriate method for checking the quality of compaction.
Abstract
For the last 25 years we have been using DMT tests to check the quality of landfill compaction. In several situations of large areas subject to earthmoving, significant pathologies [...]
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Site Exploration for Anchoring of Wave Energy Converters
T. Evans*, T. Tran

ISC2024.

Abstract
Wave energy converters (WECs), a form of marine hydrokinetic (MHK) energy device, transform the mechanical energy of water waves into electricity. They are typically held on station using anchoring systems embedded into the seafloor sediments (as opposed to, e.g., concrete gravity anchors). The design of WEC anchors is particularly challenging for two primary reasons: (1) WECs are often deployed in previously undeveloped areas of the ocean, so the engineering properties of the seabed are largely unknown; and (2) the economic margins on wave energy are quite thin, so heavily overdesigned anchor systems in response to data sparsity are not feasible. This paper describes the planning, execution, and outcomes from a dedicated in-situ testing campaign informed only by limited geophysical data a priori. A series of 22 cone penetration tests (CPTs) were performed at a 7-km2 site approximately 11 km off the United States’ west coast. Water depth was up to approximately 75 m and the target depth for the cone soundings was 10.5 m below the seafloor. Measurements indicated that much of the site subsurface consisted of dense sand and gravel, though tests identified an overlying softer layer in some parts of the site. A summary of lessons learned and recommendations for future explorations at similarly unexplored sites are provided.
Abstract
Wave energy converters (WECs), a form of marine hydrokinetic (MHK) energy device, transform the mechanical energy of water waves into electricity. They are typically held [...]
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Continuous Medusa DMT tests in a very soft clay
F. Danziger*, G. Jannuzzi, A. Pinheiro, J. Souza

ISC2024.

Abstract
The dilatometer test (DMT) has been shown very useful in providing a number of geotechnical parameters, in different types of soils. The test is regularly carried out every 0.20 m, i.e., it is a discontinuous test. Therefore, its capability of detecting variations in the geotechnical profile is conditioned by the tests interval. The Medusa DMT, however, is able to obtain continuous measurements of the A-pressure reading, thus providing a much better picture of the soil stratigraphy. Medusa DMT tests have been carried out at Sarapuí II very soft clay deposit around Guanabara Bay, in Rio de Janeiro, and a detailed soil profile was obtained. A comparison was made with piezocone tests. The stratigraphy of the deposit obtained by both tests was almost the same.
Abstract
The dilatometer test (DMT) has been shown very useful in providing a number of geotechnical parameters, in different types of soils. The test is regularly carried out every [...]
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Soil liquefaction assessment of Ecuadorian coastal region using SDMT test (Puerto Baquerizo site)
C. Ramirez, F. Arias, D. Besenzon*, S. Amoroso, K. Chunga

ISC2024.

Abstract
On March 18, 2023, a Mw6.6 earthquake hit the South Guayas coastal region (Ecuador), resulting in human fatalities and extensive structural damage. The event triggered widespread soil liquefaction evidences by significant volume of ejected material, which persisted several weeks following the event, marking the epicentral area prone to liquefaction. To assess the susceptibility to seismic-induced soil liquefaction, we performed one seismic dilatometer test (SDMT) in an area where the phenomenon clearly manifested. This study aims to evaluate and compare various established SDMT methods for predicting soil liquefaction potential under the specific 2023 seismic event. The findings are expected to enhance the understanding of liquefaction and contribute to improve seismic hazard assessment in areas along the Ecuadorian coast, which are often interested by earthquakes, as well as to the development of mitigation strategies in this earthquake prone coastal region.
Abstract
On March 18, 2023, a Mw6.6 earthquake hit the South Guayas coastal region (Ecuador), resulting in human fatalities and extensive structural damage. The event triggered widespread [...]
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Characterisation of Carse Clays Using Seismic DMT
A. O'Brien, I. Murray*

ISC2024.

Abstract
The estuarine sediments around the head of the Forth estuary deposited during and after the Flandrian interglacial are an important, economically productive regional soil horizon in Scotland. The soil has been extensively studied locally (Hight et al., 1992) at the Bothkennar EPSRC site however, to the authors’ knowledge seismic dilatometer testing using Marchetti’s Medusa apparatus has never been used to characterise the material. Taking data from a number of sites and using an automated Medusa seismic dilatometer apparatus, a complementary contribution to the characterisation of the site which includes some comments on spatial variability of the material and other observations are presented.
Abstract
The estuarine sediments around the head of the Forth estuary deposited during and after the Flandrian interglacial are an important, economically productive regional soil [...]
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