Abstract:Key block methods are applied to analysis of rock stability for underground plant in Baise hydraulic project,including analysis of unlocated,located and random blocks,block visualization,block stability analysis and reinforcement measures. In unlocated block analysis,the geometric figure of block is analyzed by determing the maximum edge length of block according to the average joint length obtained from investigation. The location of maximum key block in cavern is analyzed and displayed,so as to determine those blocks which should be considered in reinforcement design. Based on block geometry and joint shear strength,block stability is evaluated and anchor force is suggested to assure block safety. In located block analysis,actual geometry of blocks,including concave blocks are analyzed and shown by investigation of joints in underground plant. Then the anchor reinforcement program is checked accordingly. In random block analysis,joint net simulation and random block search are introduced. In the study of key block theory applied to rock engineering,some new techniques are developed,such as block geometry analysis by assuming maximum edge length of block,concave block analysis and visualization,block stability analysis and reinforcement suggestions.