Acoustic emission and fractal characteristics of saturated coal samples in the failure process

To study the acoustic emission (AE) and fractal characteristics of saturated coal samples, focusing on coal samples of No.3 coal seam in Yuwu coal mine, an experimental study was carried out to investigate the acoustic emission characteristics of the dry, natural and saturated coal samples under uniaxial compression, by using RMT-150C rock mechanics test system and AE-win E1.86 acoustic emission instrument, and the fractal characteristics of acoustic emission count sequence was further analyzed. The results show that the uniaxial compressive strength decreases when the water content of coal samples increases. The acoustic emission evolution processes of dry, natural and saturated coal samples are similar, which can be divided into three stages, that is, the initial quiet period, the active period, and the post peak quiet period. Compared with the dry coal samples, the acoustic emission count of natural coal samples reduces 49.95%, and the cumulative acoustic emission count reduces 37.04%, while the acoustic emission count of saturated coal samples reduces 77.48%, and the cumulative acoustic emission count reduces 52.17%. All of the dry, natural and saturated coal samples have the fractal characteristics, and the fractal dimension value of acoustic emission presents the phenomenon of rising, drop and maximal value, which can be used as the precursor information of dynamic disaster prediction. ©, YYYY, China University of Mining and Technology. All right reserved.