A FRACTAL DESCRIPTION OF THE PROGENY OF DOUBLE IMPACT SINGLE-PARTICLEBREAKAGE

This paper outlines the results of the double impact failure of indivi dual cores of rock, the progeny of which were described by a fragmenta tion fractal dimension. This, swing pendulum generated, data was compa red to that previously established from the single impact breakage of rock cores, and the fragmentation fractal was found to be a suitable t ool by which the two mechanisms could be assessed. The swing pendulum data was seen to adequately comply with an empiric based fractal model of fragmentation derived from the above mentioned single impact tests . Although an additional consideration was necessary to account for th e velocity of the impact event, this indicated that the model may have wider application and be relevant to the impact failure of rock in ge neral. However, ultrafast load cell testing of selected rocks illustra ted that a previously postulated function for describing the relation of fragmentation fractal and size of the parent particle did not hold. The extrapolated fragmentation fractal significantly under estimated that directly obtained from the progeny of the ultrafast load cell exp eriments. (C) 1997 Elsevier Science Ltd.