Documents published in Scipedia

• Application of Swedish Weight Sounding Test for the Geotechnical Assessment of Solar Power Plant

  J. Gargullo*, R. Luna

  ISC2024.

  
  

  Abstract

  As part of the global efforts to mitigate climate change and foster sustainable development, the construction of solar power plants has experienced significant growth in the Philippines over the past few years. This constitutes an increasing contribution to the renewable energy sector. This paper presents the applications of the Swedish Weight Sounding Test in the geotechnical assessment for solar power plant facilities. Utilizing SWST is a more portable and cost-effective way to evaluate the soil conditions crucial to establishing the solar panel arrays' foundation system and the project's overall feasibility. The penetration resistance data of SWST was employed to establish the soil stratification, soil strength, and consequently the foundation type and allowable bearing capacity. Moreover, the results were also used to assess the susceptibility of the project site to geohazards, such as liquefaction. Theoretical capacities of the helical and screw piles, the widely used foundation system for solar panels, can be derived and correlated with the results of the SWST. This paper shall present the utilization of SWST, as a supplement to SPT, primarily on the geohazard and foundation assessment for solar power plants. This study is expected to provide a reliable reference on the advantages of SWST and the selection of foundation type based on the results obtained from this cost-effective geotechnical investigation method.

  Abstract
  As part of the global efforts to mitigate climate change and foster sustainable development, the construction of solar power plants has experienced significant growth in the [...]

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• Vibro-Penetration Tests for The Evaluation of Blasting Compaction in very loose Sandy dumps

  R. Cudmani*, R. Cudmani

  ISC2024.

  
  

  Abstract

  During the so‐called vibro‐penetration test (VPT), a vertical harmonic excitation force drives a rod with a conical tip into the ground. For the evaluation of the VPT resistance, an energy‐corrected number of vibration cycles Nz10 for 0.10 m penetration is used. In order to determine Nz10, the dynamic penetration resistance, the tip and shaft resistance, the tip acceleration, and the depth of the penetrometer tip are continuously recorded and processed according to a mechanical vibro-penetration model. Calibration chamber tests, field tests, and Finite Element Analyses, which were carried out to validate the assumed penetration mechanism and to investigate the influence of the state variables (density and effective stresses) and the machine parameters (static moment, frequency, and static load) on the penetration resistance. As the force and displacement of the penetrometer are determined at the tip, an equivalent spring stiffness, which is correlated with the soil stiffness, can be calculated over the driving depth. Since vibro‐penetration resistance is closely related to the soil behavior under cyclic shearing, the VPT should be more appropriate than monotonic tests to characterize the ground response to repeated dynamic and alternating loading, e.g. pile drivability, ground compaction, and soil liquefaction susceptibility. Compared with the cone-penetration test (CPT), the VPT equipment is much lighter, the execution time is shorter, and in‐situ investigations of medium-dense to dense cohesionless soils at large depths are feasible. In this contribution, VPT and CPT are used to investigate the effect of blasting compaction in very loose dumps from opencast mines in Lusatia, Brandenburg, Germany. It is concluded that the VPT results are reproducible. In addition, Nz10 shows a clear correlation with the state variables and the VPT records before and after blasting compares well with the results of CPT.

  Abstract
  During the so‐called vibro‐penetration test (VPT), a vertical harmonic excitation force drives a rod with a conical tip into the ground. For the evaluation of the VPT [...]

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• Dynamic modulus E_kd evaluation by dynamic penetration test

  S. Lopez Retamales, M. Benz*, S. Espinoza, J. Canou, J. Dupla

  ISC2024.

  
  

  Abstract

  Dynamic penetration tests DPT have been routinely employed in the geotechnical characterization of the subsoil in different types of engineering projects. The evaluation of the results of these tests has been performed considering a limited number of parameters obtained in the field, so the definition of new parameters allows a more accurate evaluation of soil characteristics. The purpose of this paper is to present a methodology for the evaluation of the dynamic modulus (Ekd) based on the analysis of the dynamic force and velocity signals recorded in each hammer impact. Variable energy DPT tests were performed on Fontainebleau NE34 sand specimens in a K0 calibration chamber. For each hammer impact on the penetrometer, a decoupling and wave reconstruction method was applied to obtain the force and velocity signals at the cone-soil interface, which are analyzed in the frequency spectrum to obtain the Ekd modulus. The results show that it is possible to evaluate the dynamic modulus at different vertical loading conditions and independent of the impact energy level of the hammer on the penetrometer.

  Abstract
  Dynamic penetration tests DPT have been routinely employed in the geotechnical characterization of the subsoil in different types of engineering projects. The evaluation of [...]

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• Evaluation of Cone Resistance Results from Dutch Formula

  C. Forestti, C. Oliveira, M. Benz, P. Breul, B. Chevalier

  ISC2024.

  
  

  Abstract

  The Dynamic Penetration Test (DPT) is widely applied for soil field characterization. The technique is usually appreciated as a simple and cost-effective means of determine soil resistance which can be obtained either from Newtonian or from wave equation methods. While wave equation analysis has demonstrated numerous advantages in recent decades, its adoption is constrained by the need for specific instrumentation and more complex analysis. Consequently, the simpler Newtonian analysis, and particularly the Dutch Formula specified by ISO 22476-2, remains the more commonly used approach for routine geotechnical applications. To ensure its accuracy comparing to wave equation-based methods, a field campaigns were conducted on experimental sites with various soil types. The campaigns included Cone Penetration Test (CPT), which is used as a reference tool in this study, and instrumented DPTs allowing easy application of wave equation methods. Results revealed that Dutch Formula resistance values were comparable to both CPT results and those derived from wave equation methods in most cases. In addition, DF variation formula applying energy measurement seemed to underestimate cone resistance in all case examined. The study highlights the importance of applying good practice rules to enhance DPT results

  Abstract
  The Dynamic Penetration Test (DPT) is widely applied for soil field characterization. The technique is usually appreciated as a simple and cost-effective means of determine [...]

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• Investigation and monitoring to model the interaction between the Scrovegni’s Chapel in Padova (Italy) and the underlying foundation soil

  G. Dalla Santa, P. Simonini*

  ISC2024.

  
  

  Abstract

  In Padova's historic centre lies the renowned Scrovegni’s Chapel, painted by Giotto in 1303. The local subsoil primarily consists of silty sand with some layers of silt. The crypt beneath acts as a buffer against soil moisture, preventing damage to the frescoes. However, during heavy rain, groundwater rises flowing across the floor and lateral walls, therefore flooding the pavement. A pumping system is eventually activated to mitigate the pavement inundation. Several investigations including geophysical surveys, piezocone tests, and boreholes with soil sampling have been conducted to provide the subsoil geotechnical model and understand the local hydrogeological behaviour. Monitoring systems, such as piezometers, deep extensometers and optical fiber cables, track groundwater levels and long-term soil displacements. The paper aims to characterize the subsoil's stratigraphy, mechanical properties and permeabilities to model how the environmental conditions affect the ancient Chapel and ensure its long-term stability.

  Abstract
  In Padova's historic centre lies the renowned Scrovegni’s Chapel, painted by Giotto in 1303. The local subsoil primarily consists of silty sand with some layers of silt. [...]

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• In-situ experimental tests for shallow foundation design using dynamic penetration testing method

  T. Luong*, P. Reiffsteck, M. Benz Navarrete, F. Szymkiewicz

  ISC2024.

  
  

  Abstract

  To develop an advanced and innovative method for shallow foundations design with the aid of dynamic penetration testing technique, several in-situ tests are realized on various experimental sites to enrich the available database and to valid the computed results. This communication presents the field tests consisting of the Foundation Loading Tests and the Dynamic Cone Penetration Tests (DCPT): their performance, operation principles, equipment and results obtained. A direct method for bearing capacity prediction based on the measured data is also proposed, then compared to other approaches already standardized. Therefore, this study contributes to the improvement of the shallow foundations design method by providing full-scale experimental results and discussing their findings.

  Abstract
  To develop an advanced and innovative method for shallow foundations design with the aid of dynamic penetration testing technique, several in-situ tests are realized on various [...]

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• Responses of Dynamic Penetrometers according to Hammer Weight and Drop Height

  J. Lee*, G. Park, N. Kim, D. Kim, S. Kim

  ISC2024.

  
  

  Abstract

  This study characterizes the dynamic responses of hammer weight and drop height in dynamic penetration tests. The tests were conducted using an instrumented dynamic cone penetrometer (IDCP) to obtain the dynamic responses during penetration. Various hammer weight and drop height types were used at a fixed potential energy of 45.1 N∙m. The measured compression stresses and transferred energies into the rod head and cone tip were analyzed for hammer weight and drop height. The compression stress at the rod head varied with the hammer weight and drop height, whereas the compression stress at the cone tip is irrelevant to the hammer weight or drop height. In addition, the transferred energies into the rod head and cone tip increased as the hammer weight increased but decreased as the drop height increased. This study demonstrates that hammer weight and drop height should be considered when the characteristic of subsurface is profiled using dynamic penetrometer.

  Abstract
  This study characterizes the dynamic responses of hammer weight and drop height in dynamic penetration tests. The tests were conducted using an instrumented dynamic cone penetrometer [...]

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• Applicability of CPTU to characterize diatomaceous fine-grained soils: a case study in Euganean Hills (Italy)

  G. Dalla Santa*, F. Ceccato, P. Simonini

  ISC2024.

  
  

  Abstract

  Diatomaceous soils, composed of diatom fossils and clay minerals typically formed in volcanic environments, exhibit characteristics such as low unit weight, high plasticity and liquid limit, significant compressibility, and high friction angles. Despite their presence in various locations globally, knowledge about their geotechnical behavior is limited and primarily based on laboratory tests conducted on artificial samples. This paper presents data obtained from undisturbed samples of natural diatomaceous soils and discusses the interpretation of Cone Penetration Test with Pore Pressure (CPTU) data to classify these complex non-textbook soils and estimate their mechanical properties. The study area is situated in the Po Plain near the thermal anomaly region of the Euganean Hills in Northeast Italy. Three CPTUs and one borehole with the collection of four Osterberg undisturbed samples were conducted. Laboratory tests on the undisturbed samples provided values for Atterberg Limits, soil unit weight, in-situ void ratio, compressibility, and permeability, which were compared with estimations derived from CPTU data analysis. Moreover, Scanning Electron Microscope images provided insight into the distinctive microstructure of diatom microfossils embedded in a clayey matrix. Based on these comparisons, CPTU proves to be effective in estimating relevant parameters of diatomaceous soils, particularly the Soil Behavior Type (SBT) and consolidation coefficient from dissipation tests. However, the agreement in estimating the oedometric modulus is less satisfactory. Therefore, for a precise definition of the geotechnical model, it is recommended to conduct additional laboratory tests, particularly those focused on defining compressibility parameters, given the unique behavior of natural diatomaceous soils.

  Abstract
  Diatomaceous soils, composed of diatom fossils and clay minerals typically formed in volcanic environments, exhibit characteristics such as low unit weight, high plasticity [...]

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• Soil Characterisation Using a Dynamic Penetrometer

  J. Rong*, M. Nazem

  ISC2024.

  
  

  Abstract

  In offshore engineering, a geotechnical site investigation is an important step in analysis and design to ensure the integrity and serviceability of infrastructure. The Cone Penetration Test (CPT) stands as the prevailing technology for offshore soil characterisation. However, this test method requires a substantial allocation of resources for equipment transportation and operation personnel. This proves inefficient and costly for conducting comprehensive surveys over ocean beds. Alternatively, free-falling penetrometers (FFP) have attracted attention as a CPT replacement for soil characterisation. Nevertheless, these devices can penetrate only to shallow depths within soils, limiting their applicability for offshore site investigation purposes. A new device has been created to overcome this constraint, featuring a dynamic penetrometer launched by a speargun. Unlike conventional free-falling penetrometers, this apparatus can attain a greater penetration ratio, exceeding 20 times its diameter. The process of experimental testing yielded notable enhancements, particularly in effectively addressing challenges associated with tilting when attempting low-penetration depths. By implementing rate corrections into the methodology, promising results were obtained for equivalent static penetration resistance. This approach not only represents the capacity to influence future penetrometer designs but elevates the overall efficiency of in-situ soil characterisation procedures.

  Abstract
  In offshore engineering, a geotechnical site investigation is an important step in analysis and design to ensure the integrity and serviceability of infrastructure. The Cone [...]

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• Machine Learning-Based Modeling of Net Ecosystem Exchange Using Numerical Weather Data and Satellite Images

  N. Kim*, J. Cho, Y. Lee

  ISC2024.

  
  

  Abstract

  Recently, the increasing severity of climate change attributable to global warming has emphasized the imperative of carbon absorption to mitigate greenhouse gas emissions. The use of the carbon sink based on the carbon absorption and storage functions of forests is suggested as an effective alternative for domestic greenhouse gas reduction. Additionally, agricultural land cover comprises approximately 38% of the Earth's surface, underscoring the importance of comprehensively understanding the carbon cycle within not only forests but also agricultural landscapes. This significance arises from the fact that agricultural land locally amplifies seasonal variations in carbon dioxide by approximately 25% compared to vegetated areas. Consequently, a comprehensive understanding of both forest and agricultural land carbon cycles is imperative, necessitating quantitative analysis of carbon uptake in agricultural settings. Thus, this study aims to construct a machine learning-based model for estimating the net ecosystem exchange (NEE) of rice paddies in South Korea using ground flux data, meteorological variables, and satellite images. Through quantitative assessment, the NEE was determined, with a mean absolute error of 1.387, root mean square error of 2.203, and correlation coefficient of 0.872. Notably, observed NEE values demonstrating extremes in magnitude were associated with calculation errors, reflecting tendencies of both underestimation and overestimation. This phenomenon is likely attributed to the study's reliance on a limited dataset and the inherent challenges of training models across a broad spectrum of observations. To enhance calculation accuracy, future endeavors should focus on accumulating a more extensive repository of NEE flux observations and leveraging high-resolution satellite imagery and meteorological datasets for refining machine learningbased models.

  Abstract
  Recently, the increasing severity of climate change attributable to global warming has emphasized the imperative of carbon absorption to mitigate greenhouse gas emissions. [...]

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