An experimental investigation of the failure mechanism of simulated transversely isotropic rocks

This paper presents the results of an experimental investigation of the failure mechanism, including failure process and failure modes, of transversely isotropic rock. This paper employs a rotary scanner to obtain the “unrolled” images of rock specimens at different stress levels during the uniaxial compressive tests. The unrolled image constitutes a circumferential surface image of the cylindrical specimen in a single picture and facilitates the study of failure processes and failure modes. Based on the experimental results, the failure of simulated transversely isotropic rock with varied orientations at different confining pressures is classified into one of two modes: (a) sliding failure along the discontinuities and (b) non-sliding failure along the discontinuities. The latter can be further classified into one of the following three sub-failure modes: (1) tensile fracture across the discontinuities, (2) tensile-split along the discontinuities, and (3) sliding failure across the discontinuities. The failure processes of these modes are also examined in this study. Failure criterion proposed by Tien and Kuo is found to predict accurately the strength and failure modes of simulated transversely isotropic rocks.