Experiment study of acoustic emission during fracture process of pre-crack granite under uniaxial compression

In order to effectively extract the precursor information of rock mass unstable failure with macroscopic structure, granite with different angles of pre-crac k were used for experiment study of acoustic emission ( AE) during fracture process of pre-crack granite under uniaxial compression. The results showed that, the influe nce of pre-crack on the rock peak strength was significant, as the angle of precrack increased, the peak strength of the granite was reduced. As the angle of pre-crack i ncreased, acoustic emission events and acoustic emission magnitude of the granite deformation and fracture process would increase, the stress in AE precursor inform ation was greatly reduced. The stress of the intact sample reached 88.5% of the peak stress, the stress of the sample for 30° crack angle was 84.5%, and 45°crack angl e was 56.2%, 60° crack angle wass 46.3%.The AE precursor signal was more advance. The acoustic emission events during the granite deformation and failure were m ainly concentrated in the pre-crack area. Acoustic emission monitoring data can better reflect the micro rupture of the rock, and the macro structure monitoring of the ro ck mass should be strengthened.