Study on Microcracks Propagation of Shale Under Tensile and Shear Loading at Different Confining Pressures

To understand the macroscopic fracture behavior of shale under different confining pressures, it is necessary to study the process of microcrack propagation from a microscopic perspective. In this study, a cohesive zone model for heterogeneous shale based on mineral distribution was constructed. Numerical simulation experiments were conducted under different confining pressures to investigate the effects of confining pressure on the extension of microcracks under tensile and shear loading from three perspectives: microcrack morphology, acoustic emission characteristics, and mechanical responses of different minerals. This study reveals the influence of different confining pressures on the extension of microcracks under tensile and shear loading conditions in shale and their microscopic mechanisms, which holds theoretical and practical significance for the exploitation of deeply buried shale gas.