Kinematic process of the catastrophic landslide through investigation and numerical simulation

This paper presents results of a case study on the Hsiaolin catastrophic landslide, including its kinematic process and the geometry of deposition. Based on geomorphologic analysis, the landslide initiated in thick, multi-aged colluvium soils at the headwaters of a small stream upslope of Hsiolin village. A three dimensional discrete element program, PFC3D was used to model interaction between the landslide and the Hsiaolin village. The landslide converted from debris and rock slide to debris avalanche during the kinematic process. The predicted velocity of initial motion was about 5~10 m/sec from source area. Then the predicted velocity was higher than 30 m/sec on steep terrain, a velocity which permitted the debris to cross Qishanxi stream and destroyed downstream village.