Field Investigation and Dynamic Process Simulation: A Case Study of Rock Avalanche in Pusa Village, Nayong County, Guizhou Province, China

This paper geologically analyzed and numerically simulated the rock avalanche which happened in Pusa Village, Zhangjiawan Town, Nayong County, Guizhou Province, China on 28 August 2017, with approximately 5 × 10 m 3 of failure mass. The features, dynamic process and evolution mechanism of the Pusa avalanche, based on the detailed field geological survey, UAV photography and monitoring video, was analyzed in detail, and the numerical model was established to simulate the initiation-movement-accumulation process. The results show that the rock avalanche originated basically from the limestone and siltstone of Yelong Formation, Triassic which extend approximately horizontally and possess developed dissolution and subsidence. The joints within such strata have progressively evolved into fissure belt and subsidence belt resulting from long-term weathering, and the steep joints parallel to slope surface were developed due to the tectonic and unloading actions. The slope deformed and fractured because of long-term gravity and weathering actions, and meanwhile the rainstorm and mining activity accelerated the deformation of slope, which finally resulted in the overall instability of slope. The in-depth analysis to the generation and disaster-induced mechanism of Pusa avalanche is of great importance to the prevention of such accidents.