The stress and deformation of stone column-improved soft clay by discrete element modelling
This study investigated the microscopic interaction and load transfer mechanism between the column and the soft clay. The discrete element method (DEM) was used in this study to simulate a stone column-improved soft clay under a plate loading condition. The aggregate and the soft clay were simulated using particles with different size distributions. The load-displacement behavior and bulging deformation from the DEM model reasonably matched the experimental results. The change of vertical stress of the column was complex and related to the bulging deformation. The radial stress of the column generally increased with settlement and showed high value in the shallow section. The soft clay developed high vertical and radial stresses in the shallow layers and in the zone close to the column. The contact force distribution changed greatly after loading. Part of the vertical load transferred from the column to the soft clay through strong particle interactions. The coefficient of radial stress, defined as the ratio of vertical stress to radial stress within the column, changed with the settlement and showed different values at different locations.
Keywords: Discrete element method, Load transfer mechanism, Particle interactions, Soft clay, Stone columns