Research on damage failure mechanism and dynamic mechanical behavior of layered shale with different angles under confining pressure

The hydrostatic or confining pressure of deep rocks has a significant impact on the mechanical behavior of brittle materials. Especially when confining pressure is applied, the mechanical properties of rock materials will undergo significant changes. Considering that the process of shale sample subjected to impact load is in a closed container in the dynamic triaxial SHPB test, the failure process of the sample cannot be observed. Meanwhile, the activation volume of the shale sample would be large and local failure would occur in the test under the high strain rate loading. Therefore, the finite element model of shale considering the bedding effect under confining pressure was established in this study. Taking shale materials with different bedding dip angles as simulation objects, the dynamic failure characteristics of shale were studied using the dynamic analysis software ANSYS/LS-DYNA from three aspects: stress-strain curve, failure growth process, and failure morphology. The research results obtained can serve as the key technical parameters for deep resource extraction.