Application of 3D-DEM with seepage analysis to numerical simulation of rainfall-induced slope failure

Failures due to rainfall, in slopes formed from volcanic soils are frequent in Hokkaido, Japan. In this study an analytical procedure to simulate rainfall-induced slope failure is proposed. The slope failure is simulated by combining two different methods, namely discontinuous analysis based on Distinct Element Method (DEM), and seepage analysis based on Finite Element Method (FEM). In order to simulate and analyze the behavior of the soil due to changes in water content accurately, the Contact-Bond model approach is used in the discontinuous simulations. To begin with, discontinuous analysis was performed for triaxial compression tests of saturated and unsaturated soils, and seepage analysis was also performed, in order to determine appropriate input parameters for the DEM simulations. The results obtained from the two numerical simulations were combined in a DEM model of the slope where the failure dynamics were examined. With this method, the efficacy of using the Contact-Bond model approach for the failure dynamics can be analyzed. The validity of this analytical procedure was evaluated by comparing experimental results of test models with the numerical simulation.