Numerical study of the effect of high-explosive storage facility shape on the azimuthal distribution of blast-wave pressures

We report numerical simulations undertaken to understand the effects of a protective dike near an underground high-explosive storage facility. Our numerical model allowed us to estimate the peak overpressure of a blast wave around an underground magazine with or without a dike. We varied the internal length-to-diameter ratio of the underground magazine to compare the effects of magazine length. We found that the dike prevented the blast wave and detonation products from expanding along the exit direction and mitigated the peak overpressure near the dike. Our simulated results for peak overpressures outside the magazine on the ground agreed well with experimental results. The azimuthal characteristics, how the peak overpressure was reduced by the increment of the azimuth angle, were independent of the internal length-to-diameter ratio of the magazine. The presence of a dike, however, does change the shape of the iso-peak overpressure zone around the magazine exit which would determine the explosive safety quantity-distance. With a dike, the iso-peak overpressure zone is a circle, and it is an ellipse without the dike on the ground. The parameters to describe these shapes can be expressed as a linear function of the radius of the iso-peak overpressure zone of a surface explosion without any models on the ground.