Response differentiation of rock characteristics under impact loading

Abstract

An innovative dynamic test simulation system was used for impact drilling, a series of experiments were carried out on intact sandstone, limestone, gabbro and marble rocks. The reflected stress wave in the experimental bar was measured and the corresponding strain energy was calculated. The results have shown that the response degree of reflected stress wave depends on impact energy and lower threshold value of response. It is hard to detect under current technical conditions if the impact energy is below the threshold value. The peak reflected stress wave and the specific strain energy relate to rock type, strength and wave impedance. For the same type of rock, it grows with increasing impact energy, the ratio is related to the wave impedance instead of impact energy when it is over or equal to the threshold value. It shows significant differences in experimented rocks.