Numerical simulation of shear behaviour of echelon rock joint using localising gradient damage model

Abstract

In this work, the crack growth behaviour in rock joints under shear load is investigated using the localised gradient damage model (LGDM). The LGDM is shown to capture the mixed-mode fracture phenomena with mesh-independent structural response and sharp localising crack profiles using a simple isotropic scalar damage variable. A simplified staggered scheme based on an operator-split approach is adopted for numerical analyses. The shear box experiments are considered to demonstrate the predictive capabilities of the proposed scheme. Two different crack joint configurations i.e., non-overlapping and overlapping are numerically simulated and the results in terms of crack profiles and structural responses are compared with the experimental results. It is observed that the non-overlapping crack joints fail in mixed-mode whereas overlapping crack joints fail in tensile mode. Further, the non-overlapping crack joints show higher shear load capacity as compared to overlapping crack joints.