Study on the differences of acoustic emission multichannel parameters for sandstone failure under different loading conditions

The damage destruction process of rocks is accompanied by distinct acoustic characteristics, and the signal characteristics collected from different acoustic emission channels often vary. In order to investigate the characteristics and mechanisms of the different channels of acoustic emission during the rock damage process, multi-channel acoustic emission synchronous monitoring experiments were carried out for sandstone loaded damage under different loading conditions. The results show that the acoustic emission parameters of each channel in the whole process of sandstone loaded damage under different loading conditions show a common pattern, the parameters are weakly active in the elastic stage, and intensively active in the rest of the stage. However, the parameter evolution patterns and parameter amplitudes of different channels are significantly different. The cumulative ringing count curves of some channels have a large growth rate in the compaction stage and a small growth rate in the destruction stage, while the rest of the channels have the opposite pattern, and the amplitude difference in the destruction stage reach 2 to 6 times. The mechanism causing this difference is that the elastic waves caused by sandstone failure attenuate with increase of propagation distance. The different spacing between the failure source of sandstone and the sensors leads to the difference of signal strength, and the setting of the threshold value leads to the omission of the signal in some channels.