Effect of Airborne Bombs on Underground Structures

The necessity of designing safe structures to withstand an air strike on a ground surface is obvious. In order to meet this goal, the blast characteristics and propagation of intense wave caused by it in discontinues rock media is considered. After selecting a dynamic pulse caused by an airborne bomb, with a specific weight and penetration on the ground surface and calculation of the resulted crater, it is applied, in a radial shape, on the crater surface. Thereby the wave propagation and its damping in a discontinum media is investigated. The rock mass and propagation of dynamic wave in it is modeled using UDEC software. The results show that with increase in the depth of structure, its instability decreases against the blast caused by a bomb with specific weight and penetration. The existence of effective discontinuity also decreases this possibility. Under the same conditions the possibility of the structure stability increases if the slope angle against the line drawn to the center of the blast is about 60 degrees.