Numerical analysis of dynamic compaction using FEM-SPH coupling method

Abstract

This paper presents the FEM-SPH coupling method for the analysis of large deformation problems caused by dynamic compaction (DC). A 3D FEM-SPH coupling model was established in LS-DYNA to simulate the dynamic compaction process. Moreover, DC operation was also simulated separately by the traditional FEM and pure SPH in the same condition with that by the FEM-SPH coupling method. After comparing the results obtained from three simulations with data measured in field test, it was found that the FEM-SPH coupling model can be a useful tool with higher efficiency and accuracy for analysis of the large deformation problem in DC. Then the parametric analyses were performed in the proposed model to evaluate their influences on the effectiveness of compaction for ground soils. The results indicate that the splash of particle soil under impact can be diminished when a fillet treatment is made for the bottom of hammer. With a given tamping energy, DC conducted from a lower distance with a heavier hammer will bring a better effect to the reinforcement of soils. The penetration of the hammer increases with the increase of tamping energy, and the proposed method can deal with DC problem even if the tamping energy is extremely high.