An Experimental and Numerical Study of Layered Sandstone's Anisotropic Behaviour Under Compressive and Tensile Stress Conditions

The weak planes in the sandstone bedding generate anisotropy in the mechanical behavior of the rock. These discontinuities affect both the strength and deformation behavior of sandstones. Under laboratory circumstances, it is difficult to analyze the brittle fracture mechanism and the micro-cracking process brought upon by crack initiation and propagation at the grain size. In this research, the fracture behavior and the micro-cracking process of anisotropic sandstone were studied using experimental tests and the particle flow code (PFC2D). The fracture behavior of anisotropic sandstone was modeled and confirmed by comparison with laboratory findings using bonded-particle DEM modeling and embedding weakness planes (smooth-joint model) in undamaged rock (flat-joint model). The failure process at the various inclination angles of bedding planes was examined under various loading regimes. Based on a study of the effects of changing the distance between bedding planes and the inclination angle, it was discovered that the inclination angle's influence on strength is more significant than that of spacing.