A dual-mechanism tensile failure criterion for transversely isotropic rocks.

We propose a tensile failure criterion for transversely isotropic rocks that distinguishes tensile fracturing mechanisms either through the anisotropic rock matrix or along the weak bedding planes. For failure through rock matrix, we extend the isotropic tensile failure criterion by constructing an augmented normal stress component based on the alternative stress concept. Failure governed by the bedding planes occurs along the bed-parallel direction once the corresponding normal stress component exceeds the strength of the interface. We then discuss the analytical solution of rock strength and failure plane orientation for transversely isotropic rocks in uniaxial tension tests, and investigate possible shapes of the curves describing the variation of these quantities with bedding plane orientation predicted by the proposed criterion. In the end, we validate the proposed failure criterion with experimental data on four different transversely isotropic rocks and elaborate that the proposed criterion can achieve unified reproduction of various types of rock strength and failure plane orientation variation curves with bedding plane orientation. [ABSTRACT FROM AUTHOR]