An improved multi-phase weakly-compressible SPH model for modeling various landslides

Abstract

A novel weakly compressible multi-phase SPH method is developed for modeling various landslides. In this model, the multi-phase system of fluid and granular materials is regarded as a continuum with multi-viscosity and multi-density. The mechanical behavior of the granular materials is described by the μ(I) rheological model and the dynamic effective pressure. An incremental diffusive term is developed to eliminate the non-physical fluctuation in the pressure field of multi-phase flow. A dynamic calculation method of effective pressure is introduced to overcome the additional calculation and error caused by the traditional method in searching for the phase interface. A friction boundary condition called the momentum method is introduced to consider the influence of basal friction on the evolution of granular landslides. The Particle Shifting Technique (PST) of the single-phase WCSPH is introduced into the multi-phase WCSPH by the two-step shifting procedure to ensure the uniform distribution of particles in each phase and phase interface during the simulation process. The effectiveness of the incremental diffusive term is first validated using a benchmark case of the two phases hydrostatic stratified column. Then the model is applied to the numerical simulation of dry granular landslide, sub-aerial granular landslide, submerged granular landslide, and rigid landslide. The calculated results are compared with experimental results and previous numerical models to verify and evaluate the performance of the current model. Proven that this model is well consistent with experimental results and has higher accuracy than previous numerical models.