Study on the collapse perforation of thick concrete targets under internal explosion

To investigate the failure condition of critical collapse of the concrete target with finite thickness, the experiments on concrete targets with different buried depth of explosive charge under internal explosion were performed by changing the amount of explosive charge. The critical collapse thickness and critical amount of explosive charge were obtained at a certain condition of cylindrical explosive charge. With the obtained experiment data, the relationship between the critical collapse thickness and critical length-to-diameter ratio of explosive charge was found by using the dimensional analysis theory. The result implies that, as the density and diameter of explosive charge is fixed, the critical collapse thickness of concrete targets increases non-linearly with the increase of critical length-to-diameter ratio. When the length-to-diameter ratio of cylindrical explosive charge is larger than 5, the increasing tendency of critical collapse thickness is getting slower and slower. Therefore, there exists a limit of critical collapse thickness under a fixed diameter of cylindrical explosive charge.