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The complexity of the explosions makes it difficult to evaluate a munition storage site’s safety. The peak overpressure associated with a blast wave that propagates from a blast is the governing factor that determines the damage to the buildings around the area. Current codes for predicting the blast pressure from an explosion are mostly applicable for a relatively long-range explosion instead of a near-field explosion. This study evaluated the rationale for the current criteria to assess limitations in the different methods and propose an alternative approach based on experimental and numerical results. This study used a small number of explosives and a small-sized ammunition storage magazine specimen to conduct explosion experiments inside an ammunition storage magazine. The ratio of the blast pressure outside the storage magazine to that at the portal of the storage magazine was compared with the empirical equations and experiments from the references, which were more conservative than the experimental values. The optimal exponential equation was proposed after a regression analysis; this equation is applicable to 1 to 653 times the portal diameter outside the ammunition storage magazine. In terms of the effect of a retaining wall on the blast inside the storage magazine, the longitudinal’s extreme value was reduced by 37–42%, while that of the transverse blast was increased by 8–20%. In terms of the numerical simulations, the extreme value of the external blast within one to five times the portal diameter range outside the ammunition storage magazine could be predicted effectively.

This study employed C4 explosives to evaluate the overpressure response in steel tunnels subjected to external explosions. The explosive scaled distance of the C4 charge from 2.15 to 3.26 m/kg1/3 was evaluated by experiments and the hydrodynamic finite element code LS-DYNA. The numerical results are in agreement with the experimental results. A simple way to estimate the overpressure in steel tunnels was proposed in this paper. The proposed methodology is both useful and efficient and can be further developed for designing protection for military structures and other facilities against explosion.

This study used experimental and numerical simulation methods to discuss the attenuation mechanism of a blast inside a tunnel for different forms of a tunnel pressure reduction module under the condition of a tunnel near-field explosion. In terms of the experiment, a small-scale model was used for the explosion experiments of a tunnel pressure reduction module (expansion chamber, one-pressure relief orifice plate, double-pressure relief orifice plate). In the numerical simulation, the pressure transfer effect was evaluated using the ALE fluid–solid coupling and mapping technique. The findings showed that the pressure attenuation model changed the tunnel section to diffuse, reduce, or detour the pressure transfer, indicating the blast attenuation effect. In terms of the effect of blast attenuation, the double-pressure relief orifice plate was better than the one-pressure relief orifice plate, and the single-pressure relief orifice plate was better than the expansion chamber. The expansion chamber attenuated the blast by 30%, the one-pressure relief orifice plate attenuated the blast by 51%, and the double-pressure relief orifice plate attenuated the blast by 82%. The blast attenuation trend of the numerical simulation result generally matched that of the experimental result. The results of this study can provide a reference for future protective designs and reinforce the U.S. Force regulations.

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