The Influence of Soil Temperature on Blast Intensity of Buried Explosive Charges

Abstract

Soil conditions, just as soil type, particle dispersion, moisture content, degree of saturation and other parameters are influencing the intensity of a blast. None of the various existing standards present an unambiguous uniform definition of all above soil conditions for blast tests. Plasan R&D team investigates the soil parameters and their effects on blast intensity in order to produce, given a particular soil, its blast intensity with respect to reference standard utilized. Such efforts were previously presented in Ref. [1],[2],[3]. This prior research proved that the degree of soil saturation has a critical effect on the intensity of the blast. It demonstrated that soils of low density with a high degree of saturation produce a higher blast intensity than denser soils with lower saturation. Recently, in some experiments carried out at various field tests, the blast intensity and the damage observed in the tested article was more aggressive than that detected in preliminary experiments conducted at Plasan test site and predicted by the simulation. The key variance concerning those tests was weather conditions that influenced soil temperature. Those tests were conducted in wintertime. The environmental temperature was near or below freezing. Generally, no known standards specify temperature of the soil for mine blast test. There is little information in the literature about the influence of frozen soil on the blast intensity. As part of the effort to predict accurately buried mine intensity in different conditions which will include moisture and temperature effects, we conducted a series of small scale blast test, utilizing dedicated designed test apparatus, using soil temperatures between +4 to -16°C, at designated soil saturation levels. The results of these tests showed that frozen soil may double the blast intensity compare with the same soil, in terms of density and saturation, at temperature above 0°C.