Identification and risk assessment of a dangerous rock mass in high-steep slope based on 3D laser scanning

The boundary of a dangerous rock mass is controlled by the structures of rock masses, and the structural plane information can be obtained through 3D laser point clouds, which provides a data basis for risk assessments. This paper first introduces the principle of terrestrial 3D laser scanning, as well as the identification and interpretation methods of rock mass structural planes. Aiming at a high-steep slope on the left bank of a hydropower station, the location of a unstable rock mass is accurately identified based on 3D point cloud data, and its geometric dimensions and controllable structural plane occurrence are measured. The instability process of the rock mass is simulated using discrete elements, and the results show that the movement has experienced five stages: plane sliding, free falling, collision bouncing, rolling, continuous rebound until static. The maximum speed of the falling rock can reach 84.26 m/s, and the maximum bounce height and horizontal distance are 30m and 40m respectively, posing a great threat to the safety of structures and personnel during construction. This research can provide references to the identification and hazard risk assessment of dangerous rock masses on high-steep slopes.