Numerical Analysis of Dynamic Evolution Characteristics of a Large Rock Landslide in Tangjiashan

Abstract

The study of landslide dynamic characteristics and accumulation patterns is of great significance for the quantitative evaluation of landslide hazards. This paper takes the Tangjiashan landslide as a research case, a real 3D model was established based on high precision DEM data to determinate the terrain characteristics and pre- and postlandslide image data to determinate the shape and size of the sliding body. Particle flow 3D program (PFC3D) is carried out to reappear the complete movement of the Tangjiashan landslide. And the dynamic characteristic factors are monitored and analyzed such as the velocity and displacement of the landslide body. The result shows that the Tangjiashan landslide is a traction-type landslide, which lasts about 37 s in total and can be divided into four stages: destabilization and destruction, collapse and accelerated sliding, high-speed sliding, and deceleration and accumulation. The maximum sliding distance is about 642.05 m and the maximum sliding speed is about 38.67 m/s. This is a typical high-speed short-range landslide, and the speed of sliding body surface is much greater than that of other parts, which show an obvious characteristic of clastic flow. In the Tangjiashan landslide, the slip distance is the controlling factor in determining the speed of the landslide at different locations.