Buried structure protection against ground shock with hollow concrete cell array

Buried structures exhibited favorable protective capacity subjected to airburst and surface explosion, but were threatened by the subsurface detonations from earth-penetration weapons. Different from the former, buried explosion could couple significant amounts of energy to the surrounding soil, leading to strong ground shocks and thus strong loads transmitted to the buried structure. In the current study, to protect a buried RC box structure subjected to ground shock, a novel buried hollow concrete cell array was proposed and applied near the sidewalls of the structure. This protection approach took advantage of reducing explosion energy coupling to mitigate the transmitted ground shock and reduce the response of the structures. With the numerical model verified with test data and design provisions, the mitigation effect of ground shock by the hollow cell array and its protection effect on buried RC box structures were investigated. It was found that the proposed approach exhibited favorable protection effects within the concerned distance for structural protection in terms of dynamic response. The ground shock peak pressure was reduced by approximately 64.1% at the scaled distance of 0.6 m/kg^1/3, while the corresponding sidewall center deflection and support rotation of the sidewall were remarkably reduced by 87.3%. Subsequently, major governing parameters on the protection effect were discussed, including the hollow component thickness, the concrete strength, the hollow cross-section configuration, the horizontal explosion location, the explosion burial depth, as well as the explosion equivalent. Increasing hollow component thickness or concrete strength would increase the damage of the buried structure. While the protection effect of the array was influenced by the detonation location and explosion equivalent, the protection effect of the array was generally favorable. Furthermore, some design recommendations for the array were provided to facilitate the application in engineering practice.