Stress Path Testing of an Anisotropic Sandstone

The Berea sandstone used in this study is transversely isotropic with respect to elastic response, with P -wave velocities of 2,160 m∕s normal to bedding and 2,290 m∕s parallel to bedding, a variation of only 6%. Triaxial compression and extension tests involving failure by loading and unloading were performed along the two directions of symmetry. With axial stress applied parallel to bedding, the internal friction angle was approximately 55°...