Influence of different soil properties on the failure behavior of deposit slope under earthquake after rainfall

In this study, the influence of soil properties on the failure behavior and mechanism of slope under earthquake after rainfall was studied with shaking table test in the laboratory, in which the failure process of slope and instant responses of water content and pore water pressure were tested. Based on the principle of similarity, a model test was designed. The experimental results showed that soil properties exhibit significant influence on failure mode and failure mechanism of slope. Local flowslide, local failure, and creep flowslide failure modes appear in the slope exposed to only rainfall. However, under earthquake after rainfall, the other three failure modes occur, i.e., local slip failure, overall slip failure, and shallow scouring and creep flowslide failure. The spatial distribution of water content and pore water pressure are the two key factors leading to slope failure. Furthermore, due to the difference of permeability, the soil properties not only affect the spatial distribution of water content of the slope after rainfall, resulting in the peak pore water pressure which occurs mainly near the foot of the slope and near the bedrock interface in the middle and lower parts of the slope, but also affect the dissipation of excess pore water pressure in the process of earthquake. Finally, it is discovered that different types of soil lead to significant differences in the peak acceleration of slope failure. The critical acceleration of slope with coarse-grained soil is greater than that of slope with fine-grained soil. The critical acceleration of slope failure shows a close relationship with soil properties.