A DEM-FDM coupled numerical study on the deformation and failure process of the isolated stone column in soft soil

A series of DEM-FDM coupled numerical simulations were performed to study the failure process of the isolated stone column in soft soil according to the Universal Distinct Element Code. In the proposed numerical model, the stone column was represented by a rigid blocky system based on the Voronoi tessellation; the surrounding soil was represented as the continuum Mohr-Coulomb material. The settlement, bulging deformation, and failure processes were tracked during the complete loading process, which enables the column-soil interactions to be observed visually. The deformation process and corresponding failure modes of isolated stone columns embodied in soft soil are graphically illustrated according to the numerical analysis. The traditional ultimate bearing capacity prediction formulas for the isolated stone column cannot be directly used for the local shear failure mode. The soil stiffness should be the critical parameter to calculate the lateral confining stress rather than the soil shear strength.