The Effect of Simultaneous and Multi-Stage Explosions on the Response of Structures Buried in Soil

Underground structures are the best options to build command posts, shelters, weapons depots, important equipment, and defense industries. The manner in which a loading is caused by launch of airplane bombs on buried underground structures is among major issues on which relatively few studies have been carried out, and may not be considered in design of such structures. The simultaneous and Multi-step explosions of missile launches from aircraft and drones also affect the buried structural response.  Therefore, in the present study, after verifying the validity of the numerical model with a real model, a comparative study on the effect of simultaneous and multi-stage bombs on response of secure buried structures in soil was carried out using finite element method. This issue has been investigated in four cases with constant burial depth and different explosion location. The results of maximum stresses presented that, in the case of multiple-stage bombing loads, underground structures under study, in all considered situations, experienced more stress than the simultaneous explosive loading mode. The difference of these changes has been observed in some places up to about 15%.