Anisotropic mechanical behavior and failure characteristics of multi-jointed rock mass

Multi-jointed rock masses are common in nature, and the failure of a jointed rock mass may potentially cause severe engineering failure. In this paper, the anisotropic mechanical behavior and failure characteristics of a multi-jointed rock mass were numerically investigated, and the effects of rock mass size, confining pressure, and loading rate on the strength dividing points, energy evolution, and crack distribution were explored. The results demonstrated that the elastic modulus and peak strain of a multi-jointed rock mass under different loading directions had an exponential relationship with the size and loading rate, whereas the effect of the confining pressure was marginal. Moreover, the loading rate had a limited effect on the mechanical behavior characteristics. Meanwhile, the size, confining pressure, and loading rate had significant effects on the initiation stress, proportion of elastic stage, and stable crack growth stage. The rock mass energy storage limit, post-peak energy evolution, and fractal crack dimension also varied with size, confining pressure, and loading rate. The failure mode of the multi-jointed rock mass was joint shear slip + tension-shear crack penetrating the joint plane.