Abstract: To investigate the fracture mechanical behavior and failure mechanism of jointed rock mass under compression and shear load, shear tests were carried out on intact and discontinuous jointed granite. The macroscopic mechanical properties, acoustic emission signal characteristics and mesoscopic evolution law by particle flow simulation were analyzed through the experiment. A method predicting shear failure of granite was proposed by using the acoustic emission signal characteristics and its key information points. The results show that the rock integrity is damaged by the joint, and the shear modulus and peak shear strength of the rock are reduced. In addition, the existence of joints will affect the propagation path and failure mode of cracks, and the influence will be weakened with the increase of normal stress. The normal stress and joints have significant effects on the acoustic emission characteristic points. The slow growth of acoustic emission signal and the continuous decline of b value can be used as the precursor characteristics of rock shear failure. The acoustic emission signal characteristics and its key information points can be used to effectively predict the shear failure process of granite. The research results provide a reference for the shear failure mechanism analysis and stability prediction of jointed rock mass.

Key words: rock mechanics, discontinuous joint, granite, acoustic emission, failure mechanism