'Bubble-type' vs 'shock-type' loading from buried explosives

The detonation of a buried explosive is known to be highly influenced by the conditions of the surrounding soil. Depending on the moisture content this leads to two distinct loading mechanisms being generated, that of bubble-type loading in saturated soils and shock-type loading in low moisture content soils. These mechanisms have been demonstrated numerically but without spatially and temporally resolved supporting data the veracity of the numerical models cannot be examined in detail. This paper presents the results from both global impulse and local pressure and impulse measurement tests on low moisture content and saturated sand. The testing provides data that supports the loading mechanisms, allowing numerical models to be fully validated against both total impulse generated and local pressure-time histories from an array of discrete points on the loaded face.