Crack propagation laws in sandstone containing elliptical holes under compression-shear loading

To reveal the crack propagation patterns and the underlying mechanisms of controlling factors in sandstone containing elliptical holes under compression-shear loading, mesoscopic mechanical parameters for the sandstone’s numerical model were calibrated based on laboratory test results. Numerical tests under compression-shear loading were conducted for various hole inclination angles and aspect ratios, followed by analysis of crack propagation behavior and the mechanistic effects of influencing factors. The research findings indicate: (1) Peak shear stress, crack initiation stress, and their difference all exhibit a trend of first decreasing and then increasing with increasing pore inclination angle. When the hole inclination angle reaches 60°, all three parameters reach their minimum values, indicating that specimens are most prone to reaching a failure state under this condition. (2) The average crack initiation angle follows a triphasic trend with increasing inclination angle: initial increase, followed by decrease, and final resurgence, reaching maximum (30°) and minimum (120°) values at specific orientations. No significant correlation exists between initiation angles and aspect ratios. (3) While both cavity inclination and aspect ratio significantly govern crack propagation behaviors, their mechanistic controls differ fundamentally. Inclination angle dictates stress redistribution patterns, thereby controlling crack nucleation positions and propagation trajectories. In contrast, aspect ratio modulates localized stress states through geometric confinement effects, ultimately regulating crack evolution dynamics. These findings establish a theoretical foundation for stability assessment and control in cavity-containing rock mass engineering.