Modeling of layered infinite slope failure triggered by rainfall

The infinite slope is typically regarded as composed of a single-layered soil with a uniform property in various physical-based models used for modeling rainfall-induced shallow landslides. This study extends the physical-based model to consider the layered infinite slope to examine the importance of soil layer distribution for rainfall-induced shallow landslides. Hypothetical scenarios of infinite slope composed of soil layers with different thicknesses and parameters are employed to conduct this examination. The results show that pressure heads caused by rainfall infiltration are strongly related to soil layer distribution. This shows the significant influence of soil layer distribution in assessing infinite slope stability. Failure of a layered infinite slope does not necessarily occur at the impervious bottom of the hillslope soil, but may also occur at the interface between two soil layers. This result shows that a neglect of soil layer distribution could misestimate failure depth. Hence, soil layer distribution must be considered to reliably analyze infinite slope failure induced by rainfall.