The Effect of Irregularities on Soil-Air Interface Reponse Due to a Buried Charge

Abstract

Previous studies have shown that pressure loading on a target by a buried explosive is not smoothly distributed. Studies were done to explore the mechanisms that cause this uneven pressure distribution, primarily the surface instabilities caused by the explosive shockwave acting upon surface perturbations between saturated sand and air media. Small-scale tests using conical, hemispherical, and cylindrical shaped surface indentations in sand with a buried explosive were conducted to identify trends in the velocity and form of the instabilities. The velocity trends in the cones and hemispheres with regards to size are reversed, and the cylindrical imperfections cause jet velocities that are up to 200% of the cone velocities and 500% of the hemisphere velocities. Tests were conducted using sand with diminishing moisture content and larger grains, and additional tests were conducted with surfactant in the water. Lower moisture content results in the instabilities not forming, while the effects of the larger grain sand and the surfactant on the jet and dome velocities do not seem noticeable.