Investigating the Effect of Soil Moisture on the Safety of the Underground Shelters against the Waves Caused by Surface Explosion

Underground structures such as sanctuaries and tunnels are considered as important and strategic structures. The response of an underground structure to loading from a surface explosion is a major issue in passive defence. So far, many studies have been carried out on various parameters such as ground response, structure response, field experiments, etc. However, there are still many unknown and vague aspects of the explosion and its impact on the soil and structure environment. In this study, the effect of soil moisture on the safety of an underground shelter has been investigated for the different amount of stress and displacement. Autodine software has been used to model the underground shelter, and two Lagrangian and Eulerian environments have been considered. The chosen explosive charge in this study is 52.16 kg of TNT, and the data is recorded using the gauges enclosed in the model. The results show that increase in the degree of saturation of the soil layer has increased the excessive pressure from the soil, and as a result, the von Mises stress in the concrete and steel system has increased and led to the deterioration of the situation.