Abstract
The study utilizes discrete element method simulations of triaxial compression to explore the effects of bedding plane inclination and confining pressure on layered slate's mechanical properties, crack evolution, and anisotropy. Additionally, the results were analyzed using the Hoek-Brown, Ramamurthy, and Saeidi strength criteria. The findings indicate that higher confining pressures enhance the slate's compressive strength and elastic modulus, displaying a distinct ‘U’-shape because of the joint inclination angle. Furthermore, as the bedding plane inclination angle increases, the damage mode has a progressive transition from shear damage to a combination of tensile-shear damage. At lower confining pressures, the crack count in the Parallel Bond Model exhibits ‘U’-shaped behavior, while the Smooth-Joint Contact Model follows an inverted ‘U’-shaped trajectory. With increasing confining pressure, the crack distribution stabilizes, suggesting that elevated confining pressures mitigate the influence of bedding plane inclination on compressive strength. Moreover, the compressive strength anisotropy ratios decrease with higher confining pressure, whereas the elastic modulus anisotropy ratios become more prominent. The Hoek-Brown criterion was superior upon comprehensively evaluating both model fitting accuracy and generalization capabilities. The modified Hoek-Brown criterion can accurately predict the failure strength of the slate at all inclination angles with a few experimental data.