| dc.description.abstract | Tunnels perform a crucial role when it comes to the transportation system. Because of the possibility of an explosion occurring in the structure, either due to terrorism or an accident, it is important to take it into account when designing a tunnel. There is also a chance for the tunnel wall to be hit by a vehicle, which also needs to be considered in the design. This thesis investigates how an explosion from a car-bomb occurring inside a tunnel affects the tunnel wall as well as the behaviour when a car crash occurs after an explosion. By using a FEM software, different scenarios for blast and car crash can be simulated and the response of the tunnel can be studied. There are several factors that can affect the magnitude of the blast. Such factors include the weight of the charge, distance to the target surface and type of explosion. In this thesis, by changing the distance and weight of the charge, as well as tunnel thickness, several numerical analyses were performed, and the results were studied. A car collision following the explosion was also simulated and studied for some of the cases. For the collision, only the response when varying the tunnel thickness was studied. Due to a time limit, it was not possible to perform many simulations for car collision, and other parameters such as mass and velocity of vehicle were not investigated. The results considered for the simulations are the pressure, displacement, Von Mises stress and effective plastic strain for the tunnel wall. From the results it can be seen that both the charge weight, distance to the tunnel and the thickness of the tunnel have a significant effect on the damage caused to the structure. The amount of damage increases for a higher charge weight and tunnel thickness and for a reduced stand-off distance. | |