Evaluation of Tunnel Burial Depth and Section Geometry on Decreasing Destructive Effects of Surface Blast

Underground structures, especially tunnels, are among the most strategic structures for all countries, and they are a potential target of enemy weapons. Therefore, the safety of these structures and the related studies are of the great importance. In the present study, the explosion phenomenon at the surface of the ground and the effect of its wave on the tunnels which are the most important buried structures is investigated by using nonlinear dynamic analysis by ANSYS-AUTODYN software. The effect of the blast wave propagation in soil was simulated with a full geometry in a 3D environment and after ensuring the accuracy of the results, the effect of the tunnel burial depth and the geometry of the cross section in reducing the destructive effects of the explosion on the tunnel were evaluated in a 2D environment. The results indicate that increasing the depth of the buried tunnel and also using sections such as circle, horseshoe, vertical ellipse and egg shape are effective in reducing the destructive effects of the explosion on buried tunnels.