Computationally Efficient Simulation of Long-Term Landslide Motion Driven by Rainfall Cycles

Rainfall is one of the primary causes of cyclic landslide motion, with detrimental effects on landscape and infrastructure. In this study, a computationally efficient sliding consolidation model (SCM) is presented to delineate the role played by inelastic soil deformation during rainfall cycles altering the hydromechanical conditions of the landslide shear zone. The model allows the incorporation of soil constitutive laws able to quantify the 3D stress changes during rainfall. As a result, it enables to simulate the onset of failure and consequent movements during hydrologic cycles. By modelling the shear zone as a perfectly plastic frictional solid, the model shows that the evolution of the stress state can lead to different regimes of motion, in some cases, characterized by a transition from a stable creep-like behavior to a rapid increase in velocity. We also find that the transition between these regimes is intimately related to the magnitude and duration of the hydrologic forcing and the initial in situ stress conditions.