On the azimuth angle characteristics of the blast wave from an underground magazine model (VII): Evaluation of peak-overpressure distribution outside arbitrarily shaped underground magazine.

We experimentally and numerically studied the peak-overpressure distribution outside an arbitrarily shaped underground magazine to elucidate its blast pressure-based safe distance. The underground magazine model had two sections: a chamber and a passageway. The safe distance was described as a circle whose radius and center strongly depended on the considered parameters: the internal-diameter ratio between the two sections and the total-internal-length- to-chamber-diameter ratio. The results of large-scale field explosion experiments using kilogram-order emulsion explosives showed that a smaller internal-diameter ratio and a larger total-internal-length-to-chamber-diameter ratio enhanced the mitigation of the blast wave outside the magazine. The numerically simulated peak overpressures outside the magazine reasonably agreed with the experimental ones. In addition, parametric studies were conducted to describe the blast pressure-based safe distance of an arbitrarily shaped underground magazine. [ABSTRACT FROM AUTHOR]