Failure Mode and Path Analysis of High and Steep Rock Slope in Mountainous Areas, Southwestern China: A Case Study in Bowa Hydropower Station

Southwestern China has become the most concentrated area for the construction of hydropower stations in China due to its rich hydropower resources. When building a hydropower station in the Alpine Valley area, it often causes the problem of destruction on steep rock slopes because of the excavation. To solve this problem, taking the No. 3 dangerous rock mass on the left bank slope of the Bowa Hydropower Station as the research object, combined with the 3D realistic modeling method of unmanned aerial vehicles, the deformation and failure modes and paths of the dangerous rock mass were qualitatively and quantitatively discussed using the stereographic projection method and limit equilibrium method. The results were analyzed and verified using numerical simulation methods. The main findings were as follows: The failure of No. 3 dangerous rock mass was mainly controlled by the preferred planes of both sides, belonging to a multi-stage and multiple wedge-shaped failure mode. It is relatively stable under natural engineering conditions, but it may occur under extreme conditions such as heavy rain and earthquakes. The numerical simulation results show a failure form of "sliding first and then dumping", which verifies the correctness of the theoretical analysis. Research results provide certain engineering experience and scientific reference value for similar steep rock slope problems of hydropower stations.