A New Principal Formula for the Determination of Explosive Strength in Combination with the Rock Mass Strength

摘要

The goal has been to develop a simple international acceptable technical formula that can be standardized by explosive manufacturers and customers and that can be used for the determination of explosive strength regarding its fragmentation capability. A literature review showed that the first well accepted technical formula used to determine the strength of an explosive was developed by the Swede Ulf Langefors in the 1940' s and that this formula could be regarded as a paradigm shift at the time when it was developed. The formula includes two explosive properties; heat of explosion and the gas volume produced per kg of explosive. The formula was mainly developed for dynamite explosives but can not be used for ANFO and emulsion explosives. Therefore, in this paper, it is proposed a new formula for international standardization including, besides the two men-' tioned parameters, also the detonation velocity, density of explosive, density of rock and P-waoe velocity in rock. Also rock structure, confinement and initiation pattern and delay times affects the fragmentation considerably. Both explosives manufacturers and customers will benefit from this kind of development An analysis of the variation range of the individual parameters in the new developed formula are shown in the paper. For the validation of the developed formula the single hole blasting method (SHB-method) is recommended to be used, because laboratory-or half scale fragmentation test cannot give the full answer of explosive strength.