Acoustic emission response characteristics of roadway surrounding rock under cyclic disturbance loading

Disturbance loading is a key factor that induces instability and failure of coal and rock masses,and consequently triggers dynamic disasters in deep coal mining. To investigate the acoustic emission (AE) response characteristics of roadway surrounding rock instability failure under cyclic disturbance loading,large-scale physical model tests were conducted on rocklike roadway specimens using a self-developed multifunctional simulation system for rockburst. The results show that under cyclic disturbance,AE activity is predominantly concentrated in the first disturbance cycle and the final failure stage,indicating that the initial disturbance readily activates pre-existing internal cracks,while rapid crack propagation and coalescence occur during the final failure. The RA-AF characteristics further reveal that tensile cracking dominates the internal fracture process. During the instability process,dense clusters of high-amplitude AE events develop around the roadway,and the spatial clustering of these events corresponds closely to the locations of macroscopic failure, demonstrating that AE signals can effectively characterize the damage evolution and instability of roadway surrounding rock. As the cyclic disturbance amplitude increases,the surrounding rock becomes more prone to instability,accompanied by a marked increase in AE counts during the failure stage, suggesting that higher disturbance amplitudes accelerate crack propagation and energy release. Compared with other disturbance forms,ramp-type disturbance loading generates higher AE energy and a greater proportion of shear cracking during instability, indicating that the disturbance loading path exerts a significant control on the fracture mode, energy release intensity, and instability fallure mechanism of roadway surrounding rock.