عنوان مقاله [English]
Perceiving the behavior of soil under explosion loads is of a great importance to the geotechnical, mining and passive defense engineers. When soil is subjected to explosion loads and the issue of the explosives-soil-structure is posited, soil exhibits a complicated behavior. The present article tries investigating the effect of the soil’s layering type and constituent materials on the damping of the tensions stemming from the explosion, the influence of the variations on the explosion center distances to the tunnels on the ground surface as well as the changes in the weight of the explosives depending on the bomb type in all of the states. In a case-specific manner, the present article models and studies Isfahan’s subway tunnel for Soffeh-Azadi route. The Soil’s constituent materials alternatively are alluvial, sandstone as well as a combination of alluvial-sandstone layers. The modeling and analysis of this subject has been carried out by means of finite element software (FLAC). Mohr-Coulomb is the behavioral model used herein. In order to investigate the effect of the surface explosion’s dynamic load on Isfahan’s subway tunnel, a given cross-section of the tunnel’s path was modeled subject to the explosion dynamic load. Based on the analyses, the impact of the GP bombs in 100 to 2000 classes can each cause serious damages to the subsurface structures depending on the carried explosives’ weight ratios. Considering the analyses, the sandstone-made soil layers feature more damping properties in contrast to the one comprised of alluvial layers. Tunnel buried in alluvial soil can only tolerate surface explosion load originating from 56kg TNT whereas the explosion load stemming from 165kg TNT can be also withstood by buried tunnel in its sandstone layer, as well. Investigating the effects exerted by the explosion distance to the underground structures demonstrated that the increase in the explosion distance to the extent of the tunnel’s diameter (D) brings about decreases in the tunnel’s crest by 43%. The existence of the adjacent tunnels leads to the creation of interactive forces resulting from the weight of the buried structure and reflection of the explosion waves due to the rigidity of the tunnel’s wall in the environment which per se cause increase in the explosion-driven displacements.