Research on Secondary Hazard Control Technology for Open-air Shallow-buried Explosive Disposal of Obsolete Bombs

To address the secondary hazards, including flying debris, dust, shock waves, noise, and vibration, that accompany the open-pit shallow-buried explosion disposal of obsolete bombs, this paper proposes an integrated protective technology system. The system follows the main line of ‘source reduction, process attenuation, directional pressure relief, terminal interception’ and integrates multiple synergistic control measures: shaped-charge induced detonation is adopted to reduce the equivalent total explosive charge. Meanwhile, the hydrogel is used to wrap the explosive charge to lower the detonation gas temperature and impede fragment projection, and a decoupled charge pit constructed with blast-resistant fiber blankets and EPS foam is employed to reduce the peak gas pressure and achieve targeted pressure relief. Besides, the flexible protective nets are supplemented to intercept ejected stemming materials, thereby significantly mitigating the environmental impact of shallow-buried explosions. Experimental results show that the evaporation rate of hydrogel is significantly lower than that of an equal volume of water, effectively prolonging the endothermic cooling process. Under the same charge weight, the shaped charge has approximately twice the capability of a conventional charge in severing steel pipes. The centralized disposal practice of obsolete explosive articles in Wuhan further verifies that the integrated protective pit markedly narrows the dust dispersion range, with the maximum projection distance of stemming and packaging materials being 50 m, and no residual hardware was found at the site after disposal. The research findings can provide technical reference and engineering support for the safe disposal of obsolete bombs in confined sites adjacent to urban areas.