关键词: 岩石动力学, 非贯通裂隙, 霍普金森压杆(SHPB), 分形维数, 能量耗散原理

Abstract: In order to study the influence of non-penetrating cracks on rock failure characteristics under dynamic loading, splitting Hopkinson pressure bar(SHPB) is used to conduct impact tests on sandstones with different number and developed depth of non-penetrating cracks. The dynamic failure characteristics are analyzed based on fractal theory and energy dissipation principle. The results show that dynamic peak stress is more complicated in different number and developed depth of cracks. Peak strain increases with the increase in the number of cracks, and it increases at first and then decreases with the increase in the developed depth of cracks. Dynamic elastic modulus increases at first and then decreases with the increase in the number of cracks, but it decreases with the increase in the developed depth of cracks. The failure modes of specimens under different working conditions are mainly divided into three types, i.e. tension strain failure, tension strain-shear composite failure and crushing failure. The number of cracks has more significant influence on the failure mode than the developed depth of cracks. The fractal dimension, energy dissipation per unit volume and energy absorption rate of the rupturing rocks increase with the increase of the number and developed depth of cracks. Moreover, the fractal dimension and dissipation energy per unit volume are both approximately linear correlated with energy absorption rate.

Key words: rock dynamics, non-penetrating crack, splitting Hopkinson pressure bar(SHPB), fractal dimension, energy dissipation principle