Variation regulation of the acoustic emission energy parameter during the failure process of granite under uniaxial compression

The AE energy characteristics of granite specimens were tested experimentally under uniaxial compression to investigate the variation regulation of acoustic emission (AE) energy during the granite failure process. The results show that the AE energy accompanies rock deformation and failure during the entire loading process. With stress increase, AE energy of granite specimens is in dynamic variation. There is a fine corresponding relationship between AE energy and stress. Under low stress levels, AE energy is relative low and remains stable. As stress increases, in the plastic deformation stage, AE energy rapidly increases and remains at a high level indicating intense energy which is released before rock failure. This phenomenon could be considered as the precursor for rock failure. Moreover, the corresponding time point where the AE energy release rate reaches the maximum is determined as the critical point for predicting rock failure. Then AE energy sharply decreases in the failure stage and rock instability occurs.