Failure and damage modes of shallow-buried RC oil depots subjected to coupled shock wave and oil-gas explosion

To investigate the failure and damage modes of shallow-buried reinforced concrete (RC) oil depots under coupled shock wave and oil-gas explosion, a scaled model of a shallow-buried reinforced concrete oil depot was designed. The influence mechanisms of the oil depot structure, oil type and content, and explosion source location on the damage and failure modes of the concrete oil depot were studied. The results show that the blast shock wave acting on the oil depot cover causes punching-perforation failure on the blast-facing side and spalling failure on the blast-opposite side. The damage of the cover containing 50% diesel is more severe than that at 100% diesel content. For 100% diesel with the cover installed, two peaks appear during the overpressure rise stage of the shock wave. For 50% diesel with the cover installed, due to interface reflections in internal cavity, three peaks appear during the overpressure rise stage compared with the full-oil case, and the positive pressure duration of the shock wave is significantly prolonged. When the explosion is initiated at the bottom of the depot, both the cover and the entire depot structure are severely damaged. Reflected wave superposition at the corners leads to significant shear cracking at the edges of the main structure. Compared with the explosion of 50% diesel, the explosion of 50% gasoline produces a larger fireball and a longer combustion duration, but does not cause damage to the main structure of the oil depot.