Numerical Simulation of the Failure Process and Mechanical Behavior of a Rock Material with Nonpersistent Cracks Under Compression

Abstract

The failure process and mechanical behavior of a rock material with nonpersistent cracks under compression are a hot and difficult issue in rock mechanics study. On the basis of the previous research, the initial constitutive models using the \(\hbox {FLAC}^\mathrm{3D}\) code are adopted for determining the failure characteristic of the rock material with nonpersistent cracks under compression. The elastic–brittle and null models are used to simulate the mechanical behavior of the rock and the crack elements, respectively. Secondly, to simulate the crack propagation mode in the rock material, the superfine element division method is used to mesh the rock material model. As a result, the crack propagation path and the stress–strain curve of the rock material under compression are well simulated. In the adopted model, the effect of crack length, dip angle, interval, overlap distance, number and confining pressure on the crack propagation path and the rock material mechanical behavior under compression has all been taken into consideration. The calculations of the numerical model show that the uniaxial compressive strength decreases with increasing crack length, the occurrence position and the propagation path of wing. The secondary cracks vary greatly with different crack lengths and dip angles. With the increase in the crack interval and overlap distance, the interaction among the cracks decreases gradually with an increase in the compressive strength of the samples. The rock material compressive strength decreases with increasing crack number and increases with confining pressure. Finally, the validation of the simulation result is verified with the experimental model tests.