A solid-liquid model of an explosion in the ground

Abstract

Comparison of the solutions found for the example of a cord-charge explosion with the experimental data showed [8] that the theoretical relation obtained between the width of the crater and the depth of burial and size of the charge, with an appropriate choice of c can describe the experimental results. Concerning the shape of the craters, the congruity with experiment is more qualitative. In order to refine this question, a series of experiments with a surface-laid cord charge was carried out. The theoretical shape of the crater obtained in the ground explosion model described above is shown in Fig. i. The solution of this problem is characteristic in that the shape of the crater (in contrast to its size) is independent of the charge size or of the magnitude of c. Therefore, verification of the model by means of a comparison of this solution with the experimental data is particularly simple. Glass tubes (1.2 m long, 7 mm diameter, and filled with hexogen) were used as the charges and were implanted in the ground at a depth equal to its radius (flush with the surface), After each explosion the ground was sliced with a thin piece of sheet metal, on which millimeter graph paper was glued, and then the contour of the crater was traced on the graph paper. The line of the free surface before the explosion was determined from previously inscribed reference marks. In Fig. 2a-c, the curves 1 show the profiles of the craters obtained, respectively, in wet consolidated sand (density fl = 1.74 g/cm a, moisture content w = 13.7%), in water-saturated sand (fl = 1.86 g/cm a, w = 20%), and water-saturated silty ground (p = 1.9 g/cm s, w = 17%). The half-width of the crater is chosen as the scaling unit for each profile. The true width of the crater has dimensions of 34, 34, and 50 cm, respectively. It can be seen that the shape of the craters depends significantly on the properties of the soil (water saturability, plasticity). This result of the experiments leads to the necessity for improving the model of the phenomenon. Let us consider the state of the ground at the crater edge at the instant when the pressure pulse from the detonation products is transmitted almost entirely to the ground. In this