MICRO MECHANISM UNDERLYING NONLINEAR STRESS-DEPENDENT K0 OF CLAYS AT A WIDE RANGE OF PRESSURES

摘要

In order to investigate the mechanism underlying the reported nonlinearat-rest coefficient of earth pressure of clays,Ko ,at high pressure,a particle-scale model which can be used to calculate both vertical and horizontal repulsions between clay particles has been proposed.This model has two initial states which presents the clays at low pressure and high pressure,and the particles in this model can undergo rotation and vertical translation.The computation shows that the majority of particles in a clay sample would experience rotation during high pressure one-dimensional compression.In addition, rotation of particles which tends to become a parallel structure causes an increase of the horizontal inter-particle force while vertical translation leads to a decrease in it.Finally, the links between inter-particle force,micro-structure and macroscopic K0 has been analyzed and it can be used to interpret well the nonlinear changes in K0 with both vertical pressure and height-diameter ratio.