Stability Analysis of Slow-Moving Landslides Incorporating Rate-Dependent Strength

Earthen materials are widely observed to exhibit varying strength under different rates of external loading. Special concerns have been raised regarding the stability of geosystems under natural perturbations, which are typically time-dependent rather than constant. For instance, analyses of active fault and landslide movements have been conducted incorporating rate-dependent strength broadly. In this manuscript, we discussed two widely used modelling approaches to study the behavior of slow-moving landslides: one on the basis of fault mechanisms, and the other involving a sliding block on top of bedrock. The latter model, which incorporates rate-and-state friction, is chosen to study the behavior of slow-moving landslides due to its flexibility in coupling with other physical processes, such as fluid diffusion. We then present a method to assess the slope stability by tracking the behaviors of active slow-moving landslides, aiming to explore their potential for catastrophic failure. Our work demonstrates that when slow-moving landslides are subjected to small perturbations induced by precipitation or engineering activities, they can either self-stabilize at a low velocity steady state or lose stability, leading to catastrophic failure. Incorporating flow-deformation coupling, slope safety conditions can be assessed in accordance with the kinematic history and the external forcing. Our modeling framework can contribute to hazard early warning systems by examining safety conditions of slow-moving landslides.