Correlating acoustic emission sources with damaged zones during direct shear test of rock joints

Applicability of acoustic emission (AE) for localizing asperity damaged zones and damage intensity in joint surfaces was evaluated in this paper. With this attempt, rock joint samples obtained from tension splitting of the rock cores were tested under constant normal load condition. The locations of the AE sources were determined from propagation velocity of acoustic waves and by measuring the transferring time from event source to AE sensor. These sources correspond to asperity damaged zones. The AE signals generated from asperity degradation of joint surfaces were detected during shear testing. The energy of the generated signals was also measured to assess the intensity of the asperity failure. The results of this study showed that the AE method has a good capability in localizing the asperities' failure points and the intensity (energy) of the asperities' failure.