Numerical study of blast wave propagation through granular materials subjected to buried blasts

Blast wave propagation in dry sand subjected to a buried charge is numerically investigated using a charge-sand stratified configuration wherein the mass ratio between sand and charge (M/C) spans over two decades. The detonation of the central charge and the sand dynamics are modeled by the FEM-DEM method. The findings reveal the pressure-profile associated with the blast wave undergoes marked shape transition as the expansion fans catch up with the incident blast wave. The blast propagation and the associated pressure-profiles depend on the coupling between the sand and the detonation products in the central gas pocket which is in turn influenced by a variety of structural parameters. Specifically, as the M/C increases from 21 to 436, the average velocity of the blast wave decreases by 22.2%. Furthermore, a blast compaction model of sand is proposed to account for the coupling effect and justify the influences arising from key-structural parameters.