Cone penetration test in sand: A numerical-analytical approach

Ahmadi, Mohammad Mehdi; Dariani, A. A. Golestani

doi:10.1016/j.compgeo.2017.06.010

Cited by 14 publications

(3 citation statements)

References 29 publications

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“…And it is mainly chosen to calculate the inertial number to ensure the system is in quasi-static equilibrium. The recent analytical study of CPT on sands by Ahmadi and Dariani (2017) highlights that the yield zone is mainly affected by the relative density and applied stresses on the soil. Nevertheless, the penetration rate and the nature of the soil can also perhaps influence the formation of the yield zone in the cone penetration problems.…”

Section: (B)mentioning

confidence: 99%

Numerical Modeling of Cone Penetration Test: An LBM–DEM Approach

et al. 2022

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In this paper, the Discrete Element Method (DEM) is coupled with the Lattice Boltzmann Method (LBM) to model the cone penetration test of saturated granular media. The coupled numerical model was calibrated using one-dimensional consolidation theory. The results obtained from the 1D consolidation test simulation showed good agreement with the analytical equation proposed by Terzaghi. A series of LBM-DEM simulations were then carried out to understand the effect of penetration rate on the behavior of saturated granular materials during the cone penetration test. The model has predicted a significant influence on the excess pore fluid pressure and an insignificant influence on the cone resistance responses and has qualitatively captured the effect of penetration rate consistent with the experimental data. The simulation results showed that excess pore fluid pressure increased with an increase in penetration rate. The particle displacement and fluid velocity contours have provided insights into the particle behavior and fluid pressure fluctuations during CPT. The increase in excess pore fluid pressure has been attributed to the fluid pressure gradients created by the cone in the fluid system based on the penetration rate. The pore pressure distribution plots have shown a maximum pore fluid pressure below the cone region and over the cone shoulder position. A consistent evolution pattern of fabric anisotropy has been observed throughout the depth in all the penetration rate conditions. The fabric components (∅ 22 ) and (∅ 11 ) have dominated around the cone area and at the boundary region, respectively. This indicates the preferential orientation of contacts in the vertical direction at the cone region and the horizontal direction at the boundary region. The simulation results have demonstrated that the LBM-DEM model can efficiently simulate the cone penetration test and associated pore fluid pressure, including the cone-particle-fluid interactions during CPT.

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Section: (B)mentioning

confidence: 99%

Numerical Modeling of Cone Penetration Test: An LBM–DEM Approach

et al. 2022

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“…As reported by Yu, cavity expansion methods in Geomaterials have been developed since 1950s, and their wide implications lead to the cavity expansion theory as a useful and simple tool for modelling many complex geotechnical problems, including in situ soil testing (eg, Ahmadi and Dariani; Mo et al; Vali et al) and tunnelling (eg, Yang et al; Fang; et al Mo and Yu; Wang et al). Numerous analytical and numerical solutions have been proposed using increasingly sophisticated constitutive soil models by applying the principles of continuum mechanics .…”

Section: Introductionmentioning

confidence: 99%

“…Dislocation-based methods initially proposed by Elsworth 31 provided an alternative approximate method to accommodate the fluid pressure dissipation under partially drained conditions, while a pseudo-elastic material was assumed together with an incompressible flow field and a stress-decouple solution was employed to note the influence of soil rigidity to the penetration rate responses. 32 As reported by Yu, 33 cavity expansion methods in Geomaterials have been developed since 1950s, 34,35 and their wide implications lead to the cavity expansion theory as a useful and simple tool for modelling many complex geotechnical problems, including in situ soil testing (eg, Ahmadi and Dariani; 36 Mo et al; 37 Vali et al 38 ) and tunnelling (eg, Yang et al; 39 Fang; et al 40 Mo and Yu; 41 Wang et al 42 ). Numerous analytical and numerical solutions have been proposed using increasingly sophisticated constitutive soil models by applying the principles of continuum mechanics.…”

Section: Introductionmentioning

confidence: 99%

A cavity expansion–based solution for interpretation of CPTu data in soils under partially drained conditions

Gao

Yang

et al. 2020

Num Anal Meth Geomechanics

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Summary A cavity expansion–based solution is proposed in this paper for the interpretation of CPTu data under a partially drained condition. Variations of the normalized cone tip resistance, cone factor, and undrained‐drained resistance ratio are examined with different initial specific volume and overconsolidation ratio, based on the exact solutions of both undrained and drained cavity expansion in CASM, which is a unified state parameter model for clay and sand. A drainage index is proposed to represent the partially drained condition, and the critical state after expansion and stress paths of cavity expansion are therefore predicted by estimating a virtual plastic region and assuming a drainage‐index–based mapping technique. The stress paths and distributions of stresses and specific volume are investigated for different values of drainage index, which are also related to the penetration velocity with comparisons of experimental data and numerical results. The subsequent consolidation after penetration is thus predicted with the assumption of constant deviatoric stress during dissipation of the excess pore pressure. Both spherical and cylindrical consolidations are compared for dissipation around the cone tip and the probe shaft, respectively. The effects of overconsolidation ratio on the stress paths and the distributions of excess pore pressure and specific volume are then thoroughly investigated. The proposed solution and the findings would contribute to the interpretation of CPTu tests under a random drained condition, as well as the analysis of pile installation and the subsequent consolidation.

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Interpretation of CPT in unsaturated sands under drained conditions: A numerical study

Keshmiri

Ahmadi

2021

Num Anal Meth Geomechanics

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A finite difference‐based numerical model simulating the cone penetration process in unsaturated sands is presented. Mohr–Coulomb model (MCM) with simple modifications and Sun model (SM) were implemented to capture the unsaturated sand behaviour. It was shown that the cone tip resistance values resulting from the two models were fairly comparable. Predicted cone tip resistance values in dry, saturated and unsaturated sands using MCM were validated by the results of field and calibration chamber tests. Sensitivity analyses were performed, and the influence of parameters including relative density, mean effective stress and apparent cohesion due to suction on the tip resistance was investigated. Based on a large number of numerical analyses, a simple relationship was suggested to predict the cone tip resistance in dry, saturated and unsaturated sands. The accuracy of the proposed relationship was evaluated by a large database of Cone penetration test (CPT) results performed in various calibration chambers containing different sands. Finally, the applicability of the suggested equation in the estimation of the soil relative density and friction angle from CPT results was shown through useful and practical charts and illustrative examples.

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Cone penetration test in sand: A numerical-analytical approach

Cited by 14 publications

References 29 publications

Numerical Modeling of Cone Penetration Test: An LBM–DEM Approach

Numerical Modeling of Cone Penetration Test: An LBM–DEM Approach

A cavity expansion–based solution for interpretation of CPTu data in soils under partially drained conditions

Interpretation of CPT in unsaturated sands under drained conditions: A numerical study

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