Modeling rock bolt reinforcement by using the particulate interface model of dem

Rock bolt is widely used to stabilize suspended rock blocks at an excavation section, reinforce rock mass, and reduce displacement along rock joints. To simulate the rock bolt behavior in discrete element method (DEM), this study proposed a rock bolt model based on discrete element method software Particle Flow Code (PFC), which simulates the interfaces between the rock bolt and surrounding rock mass using the particulate interface model with high strength and stiffness. On the basis of the proposed model, the DEM simulation can effectively install a series of rock bolts at particular positions to form a support system. The proposed model was verified using laboratory pull-out and shear tests. A series of tunnel cases were further simulated to compare the difference among the displacement distributions of the tunnel under different rock bolt configurations. The simulation results showed that the proposed model can simulate rock bolt functions on tunnel excavation. Furthermore, the results showed that increasing the length and number of rock bolts increases the reinforced effect; however, as the length and number of rock bolts increased to an upper bound value, a limited increment was observed in the reinforced effect. The proposed model provides a useful tool to simulate the rock bolt system for tunnel engineering.