Three-dimensional discrete-continuous coupled numerical simulation of a single stone column in soft soils

The discrete-continuous coupled numerical model is used to simulate the complete bearing and failure process of a single stone column in soft soils. The three-dimensional polyhedron considering the actual gravel shape is used to simulate the stone column, and the finite difference grid is used to model the soft soils. The load-settlement curve and bulging deformation curves obtained by the numerical simulation are in good agreement with the model test results. The stone column modeled by the discrete element method can effectively reflect its deformation and failure characteristics, without using complex constitutive model. The column-soil interactions can be well revealed by the coupled simulation scheme. The bearing and failure process is summarized through the analysis on the load-settlement curve, the stress and strain field of the surrounding soils, and the contact force chains of the stone column. The relationship between the macroscopic deformation and failure behaviors of the stone column and the microscopic grain movement is summarized. The bearing mechanism of the stone column can be well explained according to the structure and shape of the force chain networks inside the column body.