Abstract: The Yichang-Zhengwan high-speed railway connecting line plays an important role to improve the passenger and freight transportation capacity in the Sichuan-Chongqing direction. The potential rockfall hazards at the slope of the Xingshan tunnel portal along the entire route are very developed, which have become a key factor affecting the safe operation of the line. In the view of the above key issues, research on the precise identification and evaluation of rockfall potentials at the portal of Xingshan Tunnel was conducted. Combined with the on-site geological mapping, unmanned aerial vehicle LiDAR topographic survey, unmanned aerial vehicle close-up high-definition photography and 3D solid modeling, the landform, stratum lithology, bedding occurrence, joint fissure development, development characteristics and distribution of potential rockfalls at the high and steep slope at the tunnel portal were identified. Furthermore, three types of typical rockfall failure modes are constructed. The stability analysis and the evaluation of three types of rockfall modes under typical and extreme conditions are performed respectively. Finally, two types of governance measures are proposed. This study provides a reference for the evaluation and treatment of the same type of geological hazards in the future.

Key words: Rockfalls, Slope, Hazard Identification, Stability, Prevention and Control