Documents published in Scipedia

• 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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