Two‐phase model for the excavation analysis in partially saturated soft soils using the particle finite element method

Abstract

A two-phase velocity-pressure stabilized formulation is proposed for the numerical analysis of mechanized excavations in partially saturated soft soils using the Particle Finite Element Method (PFEM). The fully coupled formulation is based on the theory of porous media in association with the Soil Water Characteristic Curve and the porosity-dependent Kozeni-Carman model for the realistic estimation of the soil permeability. The combination of the PFEM methodology, characterized by a global re-meshing strategy equipped with a new adaptive mesh refinement scheme for the resolution of strain localization zones in the ground, with a hypoplastic constitutive model for the description of the nonlinear behavior of the deformable soil skeleton, allows for the modeling of very large deformations, as required for excavation simulations. The PFEM model is validated based on selected geotechnical benchmark problems concerned with fully and partially saturated soil specimens. The model is further applied to computational re-analyses of excavation tests involving a single cutting tool moving in a sandbox. The reaction force-tool displacement curve for the excavation tool as well as the evolution of the deformed topology of the sand including the formation of shear zones obtained from the computational model are compared with respective experimental observations. Parametric investigations aimed at elucidating the influence of selected geotechnical parameters on the excavation process are also carried out. Finally, the suitability of the proposed PFEM-based numerical strategy for the modeling of 3D excavation problems is demonstrated by means of 3D PFEM simulations in fully saturated sand.

A nonlinear optimization method for calibration of large‐scale deep cement mixing in very soft clay deep excavation

“…In the geotechnical engineering field, many studies have made an effort to find soil parameters using the back‐analyses method 6 ; Yapage, et al., 7 Li, et al., 8 Goh, et al., 9 Zhou, et al., 10 Ohtsu, et al., 11,12 Tang, et al., 13 Leon Bal and Meschke 14 used the finite‐element program, for example, ABAQUS software and/or PLAXIS, for numerical modeling the soft soil improved by deep cement mixing (DCM) columns 15 . Waichita, et al 16,17 .…”

Analysis of the Influence of Complex Terrain around DC Transmission Grounding Electrodes on Step Voltage

“…However, the complexity of geology needs to be further studied. German scholars used the finite element method [12][13][14] to simulate saturated layered soil [15]. The electricity and heat of the soil are coupled with the groundwater around the DC grounding electrode.…”

Circumventing volumetric locking in stabilized smoothed particle finite element method and its application to dynamic large deformation problems

“…More recently, the PFEM has been very successfully applied to geomechanics problems. In particular, solutions to the saturated soils problems 8 and the partially saturated soils problems, 9 seismic failure of layered clayey slopes, 10 offshore geotechnical engineering problems, 11 and 3D soil flow problems. 12 A state-of-the-art review of the PFEM can be found in Cremonesi et al 13 The PFEM is actually an updated-Lagrangian approach with nodes treated as particles.…”