Size of craters produced by explosive charges on or above the ground surface

Abstract

The results of a series of tests performed with different amounts of explosive at short distances above and below ground level, as well as on the soil surface are briefly described. After an introductory description of both the main features of the blast wave and the mechanics of crater formation, a brief review of empirical methods for crater size prediction is presented. Next, the experimental design and the results obtained are described. The crater dimensions for underground explosions coincide with those found in the literature. For explosions at ground level the results are qualitatively described by empirical equations. For explosive charges situated above ground level, the dimensions of the craters are smaller than those observed in underground and near the surface explosions. Two new single prediction equations for this case are presented.

Numerical Evaluation of Craters Produced by Explosions on the Soil Surface

“…The results of a series of tests performed by [5] with different amounts of explosive from 1 kg to 10 kg on the soil surface are used to calibrate the material and model parameters. The explosive charges used in these tests were Gelamon 80 a NG (Nitro Glycerine) based gelatinous explosive theoretically equivalent in mass to 80% of TNT.…”

“…In the numerical analysis of this paper, the soil properties included are obtained from the actual properties of the clay soil used in the physical tests presented by Ambrosini et al [5]. However, these properties are not sufficient to fully specify the parameters required to define a Drucker-Prager Cap model.…”

“…However, these properties are not sufficient to fully specify the parameters required to define a Drucker-Prager Cap model. Therefore, the parameters required to define the cap plasticity model are determined by a best match between the material properties obtained experimentally by Ambrosini et al [5] and those quoted in the ABAQUS Example Manual [13]. The soil properties and the corresponding cap plasticity parameters used are given in Table I.…”

“…The laboratory tests reported by Ambrosini et al [5] inevitably used only small explosive charges. Accordingly further numerical solutions have been established for the crater dimensions created from the TNT charges from 20 kg to 640 kg placed directly on the ground surface to simulate more closely the situations of practical interest discussed in the Introduction.…”

“…In order to validate not only the material models and corresponding properties but also the analysis procedures; a validation stage is initially conducted by comparing the results of a series of physical tests undertaken by Ambrosini et al [5] with those obtained from detailed numerical modelling of the same physical problem. This * e-mail: nabilmnagy@yahoocom enables calibration of the model and material parameters.…”