Effects of bedding planes on mechanical characteristics and crack evolution of rocks containing a single pre-existing flaw

The existence of bedding planes in rock materials has an obvious impact on the material mechanical properties and the failure process of engineering projects. In this study, a series of pre-cracked models with different bedding plane properties (i.e., strength reduction factor, bedding plane angle and spacing) were established and simulated to fail under the uniaxial compression. The results indicate that the increases of the strength reduction factor and the bedding plane spacing lead to the increasing peak strength, the change of peak strength regarding the bedding plane angle presents a concave upward trend. In terms of crack evolution, the proportion of cracks formed in rock matrix increases concerning the increasing strength reduction factor and bedding plane spacing, the abovementioned crack proportion in models with increasing bedding plane angles firstly decreases and then increases. The rock matrix has higher mechanical characteristics than bedding planes, the change of crack proportion can account for the changing peak strength from the microscopic viewpoint. By summarizing the failure patterns, the failure of models with the 45° ~ 75° bedding plane angle is induced by cracks formed in bedding planes, which can be depicted and discussed by the plane of weakness model. The above results imply that the rock slope stability can be evaluated by analyzing bedding plane properties in the field. •Effects of bedding planes are systematically investigated by simulations.•The increase of bedding plane strength and spacing leads to the increasing peak strength.•Peak strength presents a downward concave regarding bedding plane angles.•Microcrack growth can account for the peak strength change.•Engineering stability can be evaluated by analyzing bedding plane property.