Modeling the anisotropic behavior of jointed rock mass using a modified smooth-joint model

• This study proposes a model to simulate the anisotropic behavior of rock mass.
• This model modified the smooth-joint model of DEM.
• The stress–strain curves in various joint orientations are well simulated.
• Compared with the existing joint models, the model has better agreement.

This study proposes a modified smooth-joint model using the distinct element method (DEM) to simulate the anisotropic behavior of jointed rock mass. Instead of one fixed value for the friction angle, the proposed model adopts a relation of the roughness angle and the normal stress on the joint face to consider the effect of joint roughness and orientation on the shear strength. To simulate the behavior of jointed rock mass, two contact models: the parallel-bond model and the modified smooth-joint model, were used. The first model was used to simulate the cement between the particles, and the second model was applied to simulate the sliding effect on the joint face. The proposed model was validated with the experimental results of the artificial rock mass. The simulated results show that the failure modes of the rock mass, including the split mode, mixed mode, and sliding mode, could be fulfilled. The stress–strain curves in the various joint orientations were well simulated. Furthermore, compared with the existing joint models, the proposed model has better agreement with the experimental results, especially in the mixed and sliding modes.