A Comparison of Conventional and Shear-Rate Dependent Mohr-Coulomb Models for Simulating Landslides

Landslides may cause many fatalities and heavy economic losses, so it is vital to understand their mechanics so as to take appropriate measures to mitigate their risk. Phenomenally, the loose soil behaves like frictional material in most circumstances, so Mohr-Coulomb type equations are often used to describe their movement. However, these models generally do not consider the influence of the shear-rate on the Mohr-Coulomb friction angle, so the shear-rate dependence effect on the soil flow and landslide runout is not well understood. This paper reports on an application of the incompressible Smoothed Particle Hydrodynamics (SPH) method to the dynamics of dry granular assemblies. The traditional model with a constant friction angle is compared with the modified Mohr-Coulomb model with a variable friction angle related to the shear-rate. It is found that the shear-rate dependence effect is negligible for shallow granular flows along mild slopes. With steeper slopes of the ground and larger aspect ratios of the initial soil column, the rate-dependence effect becomes more important.