Documents published in Scipedia

• 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 [...]

  • 0
  •  read

• 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. [...]

  • 0
  •  read

• 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 [...]

  • 0
  •  read

• 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 [...]

  • 0
  •  read

• 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 [...]

  • 0
  •  read

• 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 [...]

  • 0
  •  read

• 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. [...]

  • 0
  •  read

• AI Modeling for Characterization of Paddy Rice Yields under Extreme Weather Conditions Using Remote Sensing and Geospatial Data

  J. Ahn*, Y. Lee

  ISC2024.

  
  

  Abstract

  Climate change, such as increase in CO2 levels and rising temperatures, can have a significant impact on paddy rice production and increase the uncertainty of yield forecasts. This study aims to employ AI modeling for forecasting paddy rice yield and present the findings of a quantitative analysis to determine its ability to generate stable forecasts under extreme weather conditions, such as heatwaves, low temperatures, and heavy rainfall. Vegetation growth indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite product were utilized. These indices include the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), Fraction of Absorbed Photosynthetically Active Radiation (FPAR), and Near-Infrared Reflectance of vegetation (NIRv). Meteorological variables such as downward solar radiation flux, daily temperature difference, precipitation, relative humidity, and temperature were also used. Over 23 years of experimentation (2000-2022), yields under extreme weather conditions did not exhibit a significant difference from the normal period, with a Mean Absolute Error (MAE) ranging from 0.30 to 0.33 ton/ha, representing a 4-5% error of the average yield. This study presents an AI modeling methodology that enables stable predictions of paddy rice yields, even under extreme weather conditions. Future work should focus on refining input data and optimizing the model by analyzing cases of extreme weather.

  Abstract
  Climate change, such as increase in CO2 levels and rising temperatures, can have a significant impact on paddy rice production and increase the uncertainty of yield forecasts. [...]

  • 0
  •  read

• Taillings Characterization: Exploring Laser Granulometry with Machine Learning

  I. Bernardes, G. Frainz*

  ISC2024.

  
  

  Abstract

  The conventional particle size test has been a widely used method in the characterization of soils and tailings. Such information is particularly useful in the evaluation of materials deposited in tailing stacks or compacted landfills, which must follow reference particle size ranges. However, the method has limitations, the main one being the execution time, which usually lasts around three days. On the other hand, laser testing appears as a viable alternative. This innovative method obtains the grain size curve of the soil through the light dispersion pattern and lasts a few minutes, a significant improvement over the conventional method. Furthermore, this method can cover particle size ranges of up to 0.1 micrometers, while the conventional method is limited to 1 micrometer. Despite the benefits of using this equipment, the laser grain size test does not yet have specific standardization for use in the field of soil mechanics. In this context, this work proposes the use of machine learning techniques to demonstrate the existence of compatibility between both methods. To this end, tests were carried out using both methodologies on different samples of iron ore tailings and an algorithm was developed to predict the material classification. The evaluation of the results made it possible to verify the consistency and precision of the results between the two methods, reinforcing the reliability and viability of the laser test as an efficient alternative to the traditional method

  Abstract
  The conventional particle size test has been a widely used method in the characterization of soils and tailings. Such information is particularly useful in the evaluation [...]

  • 0
  •  read

• Integrated geophysical methods in identifying preferential flow paths in an earth dam

  L. Rezende, C. Aguiar*, L. Soares, C. Lemos, L. Dias

  ISC2024.

  
  

  Abstract

  The evaluation of safety conditions in dams is of utmost importance to ensure stability and often involves subsurface investigation methods. Geophysical methods have emerged as a modern and relevant alternative, often more practical than traditional direct methods. This study aims to integrate the application and interpretation of resistivity and selfpotential methods to identify preferential flow paths in a small earth dam. The investigation was conducted at a dam located on the Viçosa Campus of the Federal University of Viçosa (UFV), with three main soil layers: embankment, silty clay, and alluvium. Analysis of the results revealed potential conductive zones and negative spontaneous potential anomalies, suggesting the occurrence of piping and the presence of buried structures in the spillway area. Moreover, the geophysical investigation methodology proved effective in evaluating geotechnical characteristics and flow conditions of the dam, contributing to the foundation for future safety and stability analyses of the structure.

  Abstract
  The evaluation of safety conditions in dams is of utmost importance to ensure stability and often involves subsurface investigation methods. Geophysical methods have emerged [...]

  • 0
  •  read