A practical sequential method for simulating hydrodynamic pressure-driven landslides

Hydrodynamic pressure-driven landslides induced by precipitation and reservoir water-level fluctuations are among the most common types worldwide. Accurate multi-physical field simulations are essential for understanding the mechanisms of evolution and for reliably assessing landslide stability. In this study, a novel, practical, and simplified sequential simulation approach is proposed to model the multi-physical processes of hydrodynamic pressure-driven landslides by integrating finite element and finite difference methods. The proposed approach first employs a finite element model to simulate the time-dependent seepage field within the landslide. Subsequently, a customized interface program is developed to transfer the computed seepage field from the finite element model to the finite difference model. Finally, the finite difference model is used to simulate the resulting stress and deformation fields induced by seepage variations, while incorporating the softening effects of rainfall and reservoir water-level fluctuations on the geotechnical parameters of the landslide mass. The framework is validated using a large-scale physical model of a hydrodynamic pressure-driven landslide, and the sensitivity of key geotechnical parameters to cumulative deformation and landslide initiation time is further analyzed. The results highlight the critical role of water-induced shear strength degradation in controlling deformation behavior and landslide stability.