Underground explosion of a cylindrical charge near a buried wall

The paper investigates the explosion characteristics of a cylindrical explosive that is buried in soil close to a rigid obstacle. The soil is modeled as a bulk compressible elastic plastic medium, including full bulk locking and dependence of the current deviatoric yield stress on the pressure. The Lagrange approach and the modified variational-difference method are used to simulate the process. The pressure distribution along the rigid obstacle has been studied for various stand of distances of the explosive from the obstacle. It was shown that when the explosion is relatively close to the obstacle, the envelope of the pressure distributions (connecting the maximum stress values of all distributions along the wall) shows a maximum value that is located at some distance away from the axis of symmetry and not along the axis as is the case for a distant explosion. It was found that this phenomenon appears when the interaction of the reflected wave with the explosive cavity yields significant deformation of the cavity frontal part that it is sharply deformed and becomes planar. When the explosive stand of distance from the obstacle is moderate or large, the explosion cavity remains cylindrical during all times and the peak pressure is developed along the axis of symmetry.The paper also studies the dependence of maximum stress values of all distributions and their location on the explosive stand of distance and the cavity expansion time history.