Three-dimensional run-out analysis and prediction of flow-like landslides using smoothed particle hydrodynamics

Many landslides can often be characterized as a sort of landslides which move rapidly like flowing fluid and thus have a long run-out. They usually cause large damage and casualties especially when they are trigged by an earthquake or heavy rain. Numerical simulations of flow-like landslides are difficult due to the existence of free surface and large flow deformations. In this work, the smoothed particle hydrodynamics (SPH) method is applied to model two- and three-dimensional flow-like landslides for the run-out analysis. This is because SPH method is a meshfree, Lagrangian particle method, and is believed to be superior to conventional numerical methods in treating free surfaces, moving interfaces, and large deformations; hence, it is ideal in describing the complex fluidization characteristics in flow-like landslides. In this paper, a Bingham flow model and Navier-Stokes equations are incorporated into the SPH frame work, in which fluids are discretized by flow particles, and 3D terrain topography from GIS is represented by surface (or solid wall) particles. An improved SPH method is first applied to simulate the whole run-out processes of three flow-like landslides, which were triggered by Wenchuan earthquake that occurred in China in 2008. The effectiveness of the improved SPH method in modeling flow-like landslides is demonstrated by the good agreement of the 3D profile simulation results obtained from the present SPH simulation with field observation and results from other open sources. The SPH method is then used to predict the run-out area of Jinpingzi landslide.