Abstract: Studying the influence of different fracture inclinations on the failure characteristics of coal-bearing sandstone helps to understand the mechanism of the roof strata caving. By using PFC2D, numerical models of prefabricated fractured sandstone samples with different inclinations were established for the uniaxial compression test numerical simulation. The microscopic parameters were calibrated with macroscopic behaviors to analyze their load damage and mechanical response characteristics. Combined with the evolution of the microcrack distribution, the failure mechanism of the sample was discussed. The results show that as the fracture inclination increases, the damage evolution process and mechanical properties of coal-bearing sandstone differ, and the distribution characteristics and mechanical responses of microcracks also change accordingly. The larger the fracture inclination, the higher the peak strength of the sample during loading failure, and the failure mode tends to be more singular. Combining the distribution characteristics of microcracks, the impact of different fracture angles on the macro and micro failure characteristics of the sample was analyzed. The research results can provide reference value for engineering practice and rock mechanic’s research.

Key words: Fissure Dip Angle, Roof Collapse, Rupture Mechanism, Crack Evolution, Uniaxial Compression Test