Development and verification of coupled hydro-mechanical analysis for rainfall-induced shallow landslides

To improve the performance of rainfall-based shallow landslide warning systems, a coupled hydro-mechanical analysis framework that integrates mechanical slope analysis and hydraulic infiltration is proposed. The limit equilibrium approach for infinite slopes of unsaturated soil is coupled with 1D infiltration analysis to evaluate the transient stability of the soil mass. A hybrid testing process that combines the calculations of stress and hydraulic boundaries near the sliding surface and an element testing system capable of simulating both the stress and hydraulic states on the element boundaries was developed to verify the coupled hydro-mechanical theory. The element-level modeling reveals that the proposed coupled hydro-mechanical analysis is adequate to predict the sliding depth and time of shallow landslides. Furthermore, a time-dependent warning framework based on subsurface moisture content measurements is proposed as an alternative to rainfall-based approaches for early warning of shallow landslides.