Shale samples containing single pre-machined slots were tested under uniaxial compression directed along with bedding layers. Observed fractures were initiated by the slots, however, their further development was controlled by the shale bedding layers. Slots normal to the loading direction also cause fracturing and reduce failure load. The fracturing is initiated by tensile stress generated at the slot surface due to convergence of the initial open slot. Therefore, the presence of initial aperture in pre-existing cracks or fractures is capable of changing the mechanism of fracture generation. Three kinds of macroscopic fractures are observed: tensile fractures along bedding layers, shear fractures along the inclined direction, and buckling fractures at the final failure moment. Three types of microcracks are identified: shear microcracks produced from initial weak micro-planes unrelated to the bedding layers, tensile microcracks produced from the shear microcracks in the form of wing cracks, and shear microcracks induced by high uniaxial compression stress. The growth of wing cracks can be assisted by the bedding layers. The research results will contribute to the understanding of failure mechanisms of rocks containing prominent bedding layers.

包含单个预加工槽的页岩样品在单轴压缩下与层理层一起进行了测试。观察到的裂缝是由狭缝引发的，然而，它们的进一步发展受到页岩层的控制。垂直于加载方向的槽也会导致压裂并减少失效载荷。由于初始开槽的收敛，在槽表面产生的拉应力引发了破裂。因此，预先存在的裂缝或裂缝中存在初始孔隙能够改变裂缝产生的机制。观察到三种宏观裂缝：沿层理的拉伸裂缝、沿倾斜方向的剪切裂缝和最终破坏时刻的屈曲裂缝。确定了三种类型的微裂纹：由与层理层无关的初始弱微平面产生的剪切微裂纹、由翼裂纹形式的剪切微裂纹产生的拉伸微裂纹以及由高单轴压缩应力引起的剪切微裂纹。层理层可以帮助机翼裂缝的生长。研究结果将有助于理解含有显着层理的岩石的破坏机制。