TITLE:
DEM Simulations of Granular Soils under Undrained Triaxial Compression and Plane Strain
AUTHORS:
Guobin Gong
KEYWORDS:
DEM, Periodic Cell, Saturated, Undrained, Liquefaction, Coordination Number, Redundancy Factor
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.3 No.8,
August
26,
2015
ABSTRACT: The paper presents 3D DEM simulation
results of undrained tests for loose assemblies with varied porosities under
both triaxial compression and plane strain conditions, using a periodic cell. The
undrained tests were modelled by deforming the samples under constant volume
conditions, which corresponds to saturated soil samples. The undrained stress
paths are shown to be qualitatively similar to physical experimental results.
The triggering of liquefaction and temporary liquefaction is identified by a microscopic
parameter with redundancy factor (RF) equal to unity, which defines the transition
from “solid-like” to “liquid-like” behaviour. The undrained behaviour of
granular soils is found to be mainly governed by the evolution of redundancy
factor, and a reversal of deviatoric stress in stress path (temporary
liquefaction) is found to be due to temporary loss of contacts forming a
structural mechanism in the system where RF is smaller than unity during the
evolution.