Failure Process of a Single Stone Column in Soft Soil beneath Rigid Loading: Numerical Study

Abstract The discrete element method–finite difference method (DEM--FDM) numerical simulation was conducted to investigate the failure process and the bearing mechanism of the single stone column in soft soil beneath rigid loading. The stone column was modeled by discrete rigid blocks, and the surrounding soil was represented using the Mohr–Coulomb constitutive model. The settlement, bulging deformation, and failure process were tracked during the complete loading process, which enables the footing–column–soil interactions to be observed visually. The typical load–settlement curves and corresponding failure mechanisms are graphically illustrated according to the numerical analysis. The larger loading plate will help to enhance the bearing capacity of stone columns but not intensively. The stiffness of surrounding soils controls the final failure mode. The local shear failure mode is much more likely to happen for the single stone column beneath rigid loading when the surrounding soils are relatively soft compared to their shear strengths. The existing analytical formulas may overestimate the ultimate bearing capacity of a single stone column in soft soils.