Discrete Element Simulation of Centrifuge Test of Dry Sand Under Dynamic Compaction

Based on 2D discrete element software PFC^2D, a centrifuge test of dry sand under dynamic compaction was simulated using the sample of the same grain composition. On the basis of the physical and mechanical parameters of foundation soil in the centrifuge test, the microscopic parameters of particles were obtained through a simulated biaxial test. The settlements of tamping pit in the numerical simulation were in good agreement with the results of the centrifuge test and the field test, which proved the validity of the numerical simulation. The results show that all the time curves of dynamic stress in the soil present a single peak, which accords with actual situation. When soil mass becomes stable, the porosity is smaller than the initial one and the coordination number of particles is bigger than the initial one, therefore the soil mass after tamping becomes denser. With the increase of tamping times, the total depth of tamping pit increases, however, the settlement value each tamping decreases. The study on the microscopic characteristics of soil is helpful to grasp the process of soil compaction and guide foundation treatment of dynamic compaction.