Investigation on Properties of Rock Joint in Compression Dynamic Test

Abstract

This paper is devoted to investigate rock joint interaction with stress waves by split Hopkinson pressure bar (SHPB) during wave propagation on dynamic loading. Taking two different specimens from the intact specimen (Series N) and the joint specimen (Series J), this study focused on three aspects: the influence of joint specimens on waveform propagation, inversion analysis of rock joint parameters using the waveform transmission coefficient, and the influence of the joint on rock specimens. With an increase in impact air pressure, compared with the intact sample, the transmittance and reflectance of joint specimens showed the opposite change rule; the closure rate change process of rock joint was converted from an exponential function to a linear function; the peak strength of the intact specimens was higher than the joint specimens at the same impact pressure above 19.58%, 21.21%, 21.56%, and 22.68% (mean values), respectively; and the strain rates (mean value) of the intact specimens were respectively 1.61, 1.31, 1.20, and 1.09 times that of the joint specimens.