Failure characterization of Longmaxi shale under direct shear mode loadings

Insight into the shear failure of shale is significant for the analysis of hydraulic fracturing and wellbore stability in a shale gas reservoir. In this work, a series of direct shear tests is conducted on cubic Longmaxi shale samples with various bedding orientations, i.e., α = 0°, 30°, 60° and 90°, where the bedding orientation α is defined as the angle between the bedding and shearing direction. The anisotropies in the shear...