Run-out of the 2015 Shenzhen landslide using the material point method with the softening model

Sand and soil are comprised of large amounts of discrete particles, which may lead to a transition between solid and fluid-like states in large deformation problems. How to deal with the complex transitions between these states in granular media is the key to explaining the run-out of a landslide. The Shenzhen (China) landfill landslide exemplifies a type of large deformation demonstrating this transition between solid and fluid-like states. The soil in the landfill was mainly composed of completely decomposed granite (CDG). The landslide's run-out traveled in fluid-like fashion several hundred meters and caused casualties. In this paper, we use the material point method (MPM) based on the softening model and contact algorithm to analyze the run-out of the Shenzhen landfill landslide. MPM offers substantial advantages in numerical simulations of problems involving extra-large deformations. The latest research of landslide simulations is reviewed, and the fundamental principles of MPM are introduced in the first part of the paper. Then, the post-failure behavior of the large slope in the Shenzhen landfill is simulated with the generalized interpolation material point (GIMP) method with a softening model and a contact algorithm, respectively. The trend of the velocities and displacements of material points are calculated. Topographies of the post-failure landslide using different parameters are analyzed.