Experimental study on the response characteristic and formation mechanism for the precursor information chain of rockburst

Good understanding of the precursor phenomena is essential to the warning of rockburst. Based on the acoustic emission (AE) monitoring results of 12 rockburst experiments induced by disturbance load, the dynamic response process of rockburst precursors was revealed by the first difference of AE intrinsic trend. Considering the nonlinear evolution process of AE intrinsic trend, three precursor phenomena (including the warning precursor, subcritical precursor, and disaster precursor) were revealed in a continuous process. And then, three mechanisms were proposed to interpreted the formation of these precursors under the framework of rockburst rupture evolution process, including: (i) warning precursor dominated by the reach of maximum damage rate of intergranular rupture, (ii) subcritical precursor dominated by the formation of large-scale rupture, and (iii) disaster precursor dominated by the formation of frictional slip cracks. In addition, the promotion induced effect of dynamic frequency on precursor response time was revealed, and specifically reflected in that the increase of disturbance load frequency shortens the precursor response time.