Numerical Investigation and Analysis of Blast Wave Propagation Inside Tunnels and Consequent Pressure Calculation on Explosion-Proof Doors

Recently, most underground structures are designed and loaded under the effect of blast loads. The entrance of defensive underground structures is vulnerable to blast loading. Hence, the entrance of blast wave into the underground structures and measurement of its pressure at different sections along the structures like tunnels are very important. To study the effects of blast waves on the tunnels, first, the blast wave propagation is evaluated in open space and then the wave entrance and propagation inside the tunnel are considered. Subsequently, pressure reduction through the tunnel and at branches is investigated. The blast design load acting on the explosion-proof door is found based on calculated blast waves and blast pressure at different positions along the tunnel. Finally, application of the presented method is demonstrated using some practical examples. The results of analytical method and results from numerical simulation performed by Autodyn software are compared to assess the capability of proposed analysis regarding the estimation of pressure caused by blast wave propagation. Finally, using the results of this study, it is possible to determine the pressure applied to the blast-resistant door inside the underground structure.