Abstract:In mountainous areas of southwest China, the geological conditions are complex and earthquakes occur frequently. In addition to landslides and debris flows, earthquakes can also lead to a large number of collapse and rockfall disasters, causing serious damage to infrastructure. Badai Village, which was located along the Chenghai fault zone with high risk of earthquake and typical distribution of dangerous rock mass, was taken as the research object in this paper. The influence area of dangerous rock mass under an assumed earthquake was analyzed, and the disaster risk of the expressway at the foot of mountain was evaluated. Based on unmanned aerial vehicle (UAV) images, the position and dimension parameters of the dangerous rock mass were quickly obtained by using the image recognition technique, and the recognition accuracy reached 76.2%. Then, the parameters of dangerous rock mass were substituted into the two-dimensional numerical simulation software Rocfall, and combined with the seismic energy calculation formula, the movement distance of dangerous rock mass under seismic action was calculated. The calculation results show that the nearest distance between the highway and the impact area is only 57 meters, so protective measures such as retaining walls should be built at the foot of slope.