Study on precursors of destabilization and damage of anchor-plate-cracked surrounding rock based on critical slowing-down theory

To investigate the precursor characteristics and evolution mechanisms of anchor-plate-cracked rock mass instability, this study conducts real-time monitoring of acoustic-mechanical multi-parameters during uniaxial compression tests on anchor-plate-cracked specimens using axial force sensors and acoustic emission （AE） monitoring system. A precursor identification framework is established based on critical slowing-down theory, systematically investigating the stage evolution characteristics and precursor response patterns of AE energy rate, cumulative energy, and anchor cable axial force time-series signals. The results demonstrate significant temporal characteristic anomalies prior to specimen failure: sequential hysteresis occurs in precursor responses among anchor force, AE energy rate, and cumulative energy, with anchor force precursors responding 10 seconds earlier than AE parameters. Variance analysis through critical slowing-down theory reveals that anchor force variance first exhibits instability precursors at the end of plastic stage, 8 seconds ahead of AE energy rate variance and cumulative energy variance. All variance-based precursors precede their original parameters by 4 seconds. Consequently, the original anchor force time-series parameters and their variances are proposed as primary criteria, with AE parameter variances serving as secondary criteria. This research provides theoretical references for revealing precursor information of anchor-plate-cracked surrounding rock instability and early warning of sudden instability failures in mining engineering.