Documents published in Scipedia

• Geotechnical characterisation of tailing deposits with instrumented variable energy dynamic penetrometer: a state of art

  S. Espinoza*, G. Villavicencio, G. Suazo, M. Benz, P. Breul, L. Teissier

  ISC2024.

  
  

  Abstract

  Chile is the third country with most tailing dams worldwide (764, of which 15% active, 62% inactive, and 23% abandoned). Today, one of the main challenges of the mining industry is to ensure environmental sustainability. To achieve this, it is not only necessary to have regulations guaranteeing correct design, maintenance, closure stages, but also supervision and suitable technology enabling rapid, reliable, and cost-effective diagnosis of the overall tailings dam stability. For the last 20 years, French instrumented dynamic cone penetrometer, P.A.N.D.A®, has been used for in-depth quality control of tailings deposits, mainly due to its rapidity, portability, easy-to-use, cost-effective, and environmentally friendly testing which is based on standardized methods and able to produce immediate results. The last few years, different studies have been carried out to characterize tailings dams from a geotechnical perspective as well as to assess their spatial and temporal variability. This article presents a summary of the 20 years of Chilean experience in compaction quality control and geotechnical characterization of mine waste facilities using P.A.N.D.A® to assess the overall stability, slope analysis stability, liquefaction triggering, spatial variability of material properties and evaluation of some geotechnical parameters. Indeed, given the scale of the problem these structures represent for the community and the environment, it seemed necessary to bring together most of the work carried out in Chile to propose an innovative alternative to the rest of the mining community.

  Abstract
  Chile is the third country with most tailing dams worldwide (764, of which 15% active, 62% inactive, and 23% abandoned). Today, one of the main challenges of the mining industry [...]

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• A review of 30 years French instrumented and variable energy dynamic cone penetrometer Panda

  M. Benz Navarrete*, P. Breul, P. Moustan, G. Villavicencio Arancibia, L. Teissier

  ISC2024.

  
  

  Abstract

  Dynamic penetrometer is a worldwide practice in geotechnical exploration and the French Panda (1) lightweight variable energy is the most developed device nowadays. Widely used in France and other countries, The Panda penetrometer is relatively unknown for characterizing surface soils domain and the possibilities it offers. In this article, the authors offer a brief review of the principle of measurement, its uses, advantages and disadvantages calibration, and interpretation, as well as the different relationships with other in-situ test (CPT, SPT…) and some geotechnical parameters. A summary of the works that can be found and that are based on this technology is also presented. The overall aim is to provide the reader with a basic historical document for a better understanding of the operation and analysis of the results obtained with this device, enabling it to be integrated, as a complement, into in situ investigation campaigns.

  Abstract
  Dynamic penetrometer is a worldwide practice in geotechnical exploration and the French Panda (1) lightweight variable energy is the most developed device nowadays. Widely [...]

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• Ligthweigth and heavy-duty instrumented, servo assisted dynamic cone penetrometers for shallow soil characterisation

  M. Benz Navarrete, P. Breul, Q. Tran*, C. Forestti, T. Luong

  ISC2024.

  
  

  Abstract

  Based on the principle of the Panda® penetrometer, a third-generation of variable-energy dynamic cone penetrometer has been developed in France: the Panda 3(1). This is an instrumented dynamic penetrometer which, by measuring strain, acceleration, and displacement on the rods, close to the anvil, and then decoupling the deformation waves created by the impact and propagating within the rods during penetration, makes it possible to obtain for each blow, at the soil/cone interface, a dynamic load penetration curve, called DCLT curve. Several experimental and numerical studies have been carried out to develop different techniques for processing DCLT curves and dynamic signals to assess input energy, dynamic and pseudo static cone resistance, dynamic stiffness, elastic modulus, and compressional wave velocities of soil. This technique has been adapted to the DPSH cone penetrometer (ISO 22476-2), for which it was necessary to servoassisted the impact force as a function of the soil penetration obtained after each blow to improve then the quality of the signals and DCLT curves obtained. Recently, in France, a vast experimental program involving two universities and two geotechnical companies was carried out to develop this new technique. A large laboratory and in-situ test data base was performed. After a brief presentation of the theoretical and technological development of this new technique is presented.

  Abstract
  Based on the principle of the Panda® penetrometer, a third-generation of variable-energy dynamic cone penetrometer has been developed in France: the Panda 3(1). This is an [...]

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• 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, 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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