ABSTRACT

ABSTRACT: Experiments were designed to test the hypothesis that the energy to crush explosively damaged rock is less than that for intact rock. It has been found that ultrasonic velocity and density of "crack-like" defects are closely related to the magnitude of energy dissipation in the form of new fracture surface energy. Crack-like defects increase as shock energy dissipated in rock material increases. Measurements following shock loading indicate that ultrasonic velocity in rock partially recovers with time. It appears that compressive strength is independent of shock-treatment. Energy efficiency required for creating cracks in less competent (sedimentary) rock may be much lower than for more competent (igneous) rock. Shock induced damage on fragmentation is measurable at the levels of explosive energy delivered by the split "Hopkinson" pressure bar device.

Keywords:
metals & mining, Reservoir Characterization, strength, postshock specimen, crack-like defect, defect, comminution, process zone, compressive strength, shock loading
Subjects:
Reservoir Characterization
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1994. A.A. Balkema - Permission to Distribute - American Rock Mechanics Association
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