In recent years, localized torrential rainfall caused by abnormal weather happens frequently, which triggers numerous sediment disasters accompanied with slope failure. Generally, slope stability analysis is performed, considering the parameters of the soil layers as homogeneous. However, in fact, soil particle configurations vary with depth, due to the influence of weathering. In this study, numerical simulations are performed with the reduction of cohesion and increment of friction angle taking into account the ground weathering with depth, utilizing the finite difference method (FDM). There are two types of failure modes, failure of whole weathered soil layer and surface of lower slope. Based on these results, it can be concluded that cohesion has greater impact for shear resistance force than friction angle in surface layer, conversely, at the boundary between weathered soil layer and strongly weathered rocks, friction angle has a greater impact on shear resistance force than cohesion.
In recent years, localized torrential rainfall caused by abnormal weather happens frequently, which triggers numerous sediment disasters accompanied with slope failure. If there is a technique to detect a slope which has potential of failure or may present behavior of failure, it would greatly contribute to slope disaster preventions. During the heavy rainfall, saturability of the ground increases rapidly with water flow. It is considered that pore air closing is caused with rapid water flow in some cases. Since natural slope is often unsaturated, it is required to consider the effects of pore air pressure. Generally, slope stability analysis is performed, considering the parameters of soil layer as homogeneous. However, as a matter of fact, soil particle configurations vary with depth due to influence of ground weathering. In this study, coupled stress-flow analysis is performed by calculating two-phase flow, taking into account the effects of pore air pressure. Furthermore, the impacts of weathering on slope stability are also investigated.
