Abstract: To address the limitations of traditional discontinuity surveys,which are often hazardous and challenging,we deployed Unmanned Aerial Vehicle (UAV) photography to capture data on high and steep rock slopes safely and efficiently.This approach enabled us to construct a 3D point cloud model detailing the rock mass structure of the slope.Through analysis of the 3D point cloud,we extracted critical parameters such as the orientation,spacing,and persistence of rock discontinuities.Subsequently,we generated a Discrete Fracture Network (DFN) model for the slope’s rock mass structure.Field validation was conducted on a precipitous rock slope near the Kamenziwan landslide in Zigui,Hubei Province.The discontinuity data retrieved from the UAV-derived 3D point cloud demonstrated sufficient accuracy,thereby proving the approach’s effectiveness and practicality.The slope’s six clusters of discontinuities had average spacings ranging from 0.46 m to 1.01 m and extents from 0.82 m to 12.57 m.The obtaied data of discontinuities provides reliable base for rock structural model establishment and slope stability evaluation.

Key words: high and steep rock slope, 3D point cloud obtained from UAV survey, orientation of discontinuities, spacing between discontinuities, ductility of discontinuities