Research on Sliding Mechanism of Slope with Thick Accumulation Horizon under Rainfall Condition

Abstract

With a certain thick accumulation landslide as the example, and based on the theory of the unsaturated soil mechanics, this paper has used of finite-element method to calculate and analyze the slope seepage and dynamic stability under the condition of rainfall infiltration, and studied the time effect of the water movement in the slope mass on the slope stability. The results showed that the loose structure of the slope accumulation body, the poor soil strength, the large gradient at the slope front edge and excavation at the slope toe have provided a convenient condition for landslide formation. Under heavy rainfall, the deformation instability firstly occurred near the slope toe, and then pulled the slope rear edge and caused the tensile fissures. The rainwater infiltrated along the slope surface, formed the seepage field in the slope body and weakened the rock-soil mass parameters. Meanwhile, the saturated runoffs formed on the slope surface generated the downward seepage force on the slope front edge, and promoted the slope front edge to slide and triggered the slippage of the hierarchical slopes. In the initial stage of the heavy rainfall, the safety factor of the landslide reduced rapidly, which easily caused the landslide.