Rigid Plastic FE Slope Stability Analysis Combined With Rain Fall Water Infiltration

Abstract

This paper presents a new slope stability analysis regarding rainfall-induced landslides by coupling a saturatedunsaturated seepage analysis and a rigid plastic finite element method (RP-FEM). Currently, a more valid and reliable disaster prevention system detecting the risk of slope instability due to sudden intense rainfall is required in Japan. However, conventional slope stability methods often fail to predict this new type of landslides. Therefore, the aim of this study is to propose the new slope stability analysis method in the context of rainfall infiltration. This method introduces the effect of seepage force, an increase of unit weight and a reduction of apparent cohesion due to the change in soil suction to obtain the slope stability load factors and collapse mechanisms. Consequently, this method can provide the relatively accurate and valid analysis results, which can be well compared with experimental data. Moreover, it is ascertained that this method can evaluate the different type of slope failure mechanisms: an initial small failure at the toe of the slope caused by the seepage forces and a large-scale failure due to the degradation of the soil apparent cohesion.