3D modeling of flow-like landslide propagation using smoothed particle hydrodynamics (SPH)

Abstract:

Giant landslides usually cause catastrophic damage and casualties, especially for landslides with high mobility, displaying flow-like performance and long-runout distance. In recent studies, numerical simulations of the landslide propagation have mainly been carried out in continuum mechanic frameworks. One of these approaches is using the Mohr-Coulomb law coupled with a depth-averaged method, which assumes the landslide body has a constant depth and move with the same velocity (i.e., 2D depth-averaged flow). Moreover, the Mohr-Coulomb model has only been used to consider the interaction of the flow with the solid basal boundary surface, but not to describe the interaction between the gains. Although the Mohr-Coulomb model, coupled with the depth-averaged method, has been applied successfully in simulating landslides, it cannot obtain full dynamical and internal pressure of soils, especially when topography has significant changes. Therefore, it is important to use a 3D method to constitute a model that can fully describe the friction between grains. In this study, a Smoothed Particle Hydrodynamics (SPH) method is adopted to model 3D flow-like landslides. SPH is an adaptive, meshfree, Lagrangian particle method, which is suit to simulate free surfaces, moving interfaces, and large flow deformations. Both the Drucker-Prager (DP) model and the non-Newtonian rheology Drucker-Prager (RDP) model are used to describe soil behavior and incorporate them into the SPH framework to describe elastic-plastic soil behavior. The accuracies of these two models are assessed in modeling the Baige landslides, China, 2018. The 3D profile simulation results, such as the runout distance, the thickness of deposits, and the deposit area from SPH simulations show good agreements with field data. Therefore, the SPH method can provide an effective tool to investigate the flow mechanism of large-scale landslides.