The Fragmentation of Granite Cylinders Using High Explosives.
Crum-SV; Rholl-SA; Stagg-MS
Proc 6th Ann Symp on Explosives & Blasting Research Soc Explosives Eng 1990 :179-192
As part of its ongoing research concerning rock fragmentation by blasting, the U.S. Bureau of Mines has undertaken a series of test blasts where six cylinder-shaped pieces of granite rock were fragmented using high explosives. The tests were intended to (1) establish a dataset that could be used in the development and verification of theoretical models that simulate rock blasting and (2) add to the fragmentation data currently being collected by Bureau researchers. The cylindrical geometry was chosen so that the fragmentation could be directly compared to two-dimensional computer simulations that assume an axisymmetric configuration as well as more sophisticated three-dimensional models. The granite cylinders, carnelian granite and charcoal granite, ranged in size from about 0.46 Meter (18 inches) to 0.58 (23 Inches) in diameter by 0.91 Meter (36 inches) to 1.52 Meters (60 inches) in length. Physical rock properties tests performed on the charcoal granite cylinders indicated that the rocks did in fact have similar physical characteristics. Petn-based detonating cord and dynamite were used as the explosive charges, and estimates of the values of some important physical properties are given. Significantly coarser fragmentation was produced from a blast that used dynamite as the explosive charge. Fragment velocities were calculated using photographic data from the sixth test, which was shot unrestrained in a quarry and filmed with high-speed cameras.
Proc. 6th Ann. Symp. on Explosives & Blasting Research. Soc. Explosives Eng., 1990, PP. 179-192