Simulation of Underground Structures Explosion using Finite Difference Method for Different Applications

Analysis of underground structures under blast has challenges due to the complexity of blast dynamic loading and soil behavior. Due to the role of underground structures as a shelter and the vulnerability of these structures to explosive loads, it is vital to investigate and analyze the effect of explosions on these structures. The aim of this study is to investigate the effect of explosive projectile distance from the underground structure and the diameter of the explosive sphere on the underground structure. For this purpose, using the finite difference method and dynamic analysis, the underground structure was simulated for different distances of the explosive projectile and different diameters of the explosive sphere. In this study, the propagation of explosion waves in a spherical manner was considered by applying an explosion pressure on the wall of the explosive sphere. The results show that with increasing the distance of the underground structure from the center of the explosion, the maximum soil pressure on the maintenance system as well as the bending moment and axial force in the canopy and wall of the tunnel maintenance structure decrease exponentially. In addition, after the explosion wave reaches the tunnel maintenance system, the displacement and vertical velocity of the storage system particles in the tunnel crown is the highest. As the diameter of the explosive sphere increases, the bending moment at the crown and wall of the tunnel increases almost linearly, which is three times the slope for the tunnel crown