Simulation of blast-induced rock tunnel damage using a 3D numerical model

The field tests conducted by the American Engineering Research Associates (ERA) provided important results about the distribution and extension of the damage zones and the failure area that occurred in unlined tunnels as a result of buried explosions in the rock mass surrounding these tunnels. Despite the importance of these results, they did not include specific values for the failure thickness and the fracture angle in the damaged tunnel sections. In the current study, a 3D numerical model is used to simulate one of ERA’s tests using ABAQUS. In this model, the impact of a buried explosion on a tunnel located at (5m) away from the center of the detonation is studied. The results of this model are in good agreement with the published results of ERA’s tests. In addition, the current numerical results give complete values for the change in the failure thickness and the fracture angle over the entire length of the damaged zones of the tunnel. The results of the current study show that the thickness of the failure remains almost constant beyond damage zone 1, while the angle of the fracture decreases remarkably as the charge-to-tunnel distance increases, which causes a decrease in the failure area.