Abstract: The stability of rock engineering is strongly dependent on the shear strength of jointed rock mass. Based on the particle flow code (PFC2D), the reasonable mesoscopic parameters are selected in combination with experimental results to analyze the meso-properties of crack propagation, energy transmission, and acoustic emission phenomenon of jointed rock. The strength models and failure patterns of jointed rock are numerically simulated. The main research results are summarized as follows. Abrasive and shear failure patterns heavily exist in jointed rock, and different failure patterns are corresponding to different strength models. Rock mass is damaged along joint plane with the increase of shear deformation. Normal cracks prevail within elastic stage, whereas shear cracks dominate along the rough surface within plastic stage. The joint plane slides owing to appearance of crushed zone induced by the coalescence of R and P cracks. Boundary energy is mainly converted into strain energy and more normal cracks are generated prior to the peak shear strength. With the increase of shear stress, the friction energy grows rapidly and a large amount of shear cracks are produced at the same time. Compared with experiments, PFC2D can be used to simulate the shear properties of jointed rock mass well, which remedies the challenge of simulating behaviors of jointed rock at meso-scale in the laboratory test and provides a useful reference for further research on direct shear tests of jointed rock mass.

Key words: jointed rock, joint, direct shear test, particle flow code, crack evolution