Numerical Modeling of Damage Caused by Internal Explosion on the Tunnel Concrete Lining

In general, due to the role of traffic tunnels, structural safety and defense considerations in these structures are very important. The structural lining of the tunnel can cause a lot of damage under the internal explosions resulting from malicious operations. Therefore, it is important to investigate the impact and damage caused by it. In this paper, the gas explosion at a height of 3 meters above ground level in the middle of the tunnel is modeled as the energy equivalent of 250 kilograms of TNT. A fully coupled numerical model has been made as the fluid-structure interaction (FSI) effects. To evaluate the dynamic parameters of the structure, the displacement and velocity in five points of the tunnel were investigated. In this research, engineering characteristics of one of the existing tunnels have been considered and two D shape and circular cross sections with a width of 6 meters are used to develop models. The overall results indicate that in because of the damage caused by the internal explosion, the tunnel is damaged and the maximum velocity generated at the D shape cross section is larger than the circular section, but the displacement is lower.