Abstract
Trinitrotoluene (TNT) equivalency converts an explosive into the weight of TNT that will result in the same explosive power, which can then be used to calculate its blast parameters. However, the blast parameters of an explosive charge depend on not only its weight but also its shape. In this study, field experiments were conducted using cylindrical emulsion explosive (EMX) charges with weights of 1-80 kg. The height between the center of the EMX charge and ground surface was fixed, and the explosion was initiated from the center of the top face. The blast parameters of the peak overpressure and scaled positive impulse were then used in empirical equations based on hemispherical and cylindrical TNT charges to estimate the explosive power of the EMX charges. The differences of the TNT equivalencies based on the peak overpressure and scaled positive impulse were 18.8% using the hemispherical TNT and 2.5% using the cylindrical TNT, respectively. When the shape, height above the ground surface, and initiation point of the TNT and EMX charges were similar, their blast waves had similar characteristics, and the TNT equivalency of the EMX charge was almost independent of the blast parameter used (i.e., peak overpressure or scaled positive impulse). These results emphasize the necessity of ensuring that the experimental conditions for two types of explosives match as closely as possible to compare their explosive powers.
