Numerical Simulation on the Effect of Rock Joint Roughness on the Stress Field

Abstract

In view of the influence of Joint Roughness Coefficient (JRC), which is for quantitative description of the joint surface roughness, on the stress field of the rock mass, compression test and shear-compression test were simulated on models with different joint roughness. The photoelasticity technique is applied to examine the feasibility of numerical simulation. The results show that numerical simulation results are in agreement with the results of photoelastic experiments. The stress concentration area is distributed near the joint plane. Thus, the joint plane controls the shear strength of the rock. In compression test, the maximum shear stress of the model is proportional to JRC and the normal pressure. In shear-compression test, when the ratio of the axial shear to the normal pressure is small, the maximum shear stress is nonlinearly positively correlated with JRC. When the ratio of the axial shear to the normal pressure is relatively large, the relationship curve between the maximum shear stress and JRC is parabolic. When the JRC is small, as the ratio of the axial shear force to the normal pressure increases, the maximum shear stress changes abruptly, and the maximum shear stress after the mutation decreases significantly. The reason is that the upper and lower parts of the model have slipped, resulting in a redistribution of stress. In addition, when the JRC is 6 to 12, it is more likely to cause stress concentration.