Research on key block search and reliability of jointed rock slope

Abstract The key blocks are the core factors affecting jointed rock high slopes. How to quickly identify key blocks in complex rock high-steep slopes and obtain block information is one of the key issues to be solved in engineering. Due to the numerous joint fissures in jointed rock slopes, which bring complexity and variability to the search for key blocks, this paper proposes a targeted and flexible key block search method based on the finiteness theorem and movability theory of block theory. Non-contact photogrammetry technology is used to collect the structural plane information of the slope rock mass in the study area, and the data is imported into Trimble RealWorks software to establish a 3D model of the rock high-steep slope. Through the processing of point cloud data, parameters such as the sliding direction, structural plane intersection points, area, and volume of key blocks in the slope are obtained, and key blocks are searched from a geometric perspective. Finally, according to the full-space stereographic projection theory, movable fissure blocks are identified, and the residual sliding force calculation theory of movable fissure blocks is used to determine the key blocks in the slope free face, and the sliding instability mode of jointed rock slopes is studied. The application of this theory in the Fujian Yongtai high-steep slope project has verified that the method has the advantages of strong pertinence, simple operation, and good adaptation to the judgment conditions specified in relevant codes. The research results provide a scientific basis for further revealing the key blocks of jointed rock slopes.