Since the confining strain increases, the increase in resistance to longitudinal crack propagation brings about a gradual changeover of shale failure method from longitudinal to inclined shear failure that demonstrates an escalation in rock plasticity. When the confining pressure reaches 30 MPa, there are still nearby shear microcracks round https://vertechs1.blogspot.com/2025/12/mastering-depths-how-vertechs-is.html