Acoustic emission characteristics and failure prediction of defective cemented gangue-fly ash backfill under seepage-stress coupling

Aiming at the problem of seepage-stress coupling failure instability of cemented gangue-fly ash backfill (CGFB) with defects, the triaxial compression test and acoustic emission (AE) monitoring test of the CGFB were carried out in this paper. The strength characteristics of defective CGFB under seepage-stress coupling were analysed，the variation rules of AE parameters (ring count, b-value and entropy value) in the failure process were systematically studied. It is found that the AE parameters (ring count, b-value, and entropy value) of backfill with defects under seepage-stress coupling have a ‘mutation’ phenomenon, which can be used as a precursor feature of failure instability of backfill. Combined the grey-cusp catastrophe theory, a failure prediction model of backfill based on AE parameters (ringing count) was established, and the seepage-stress coupling fracture of backfill with defects was effectively predicted, indicating that the model is feasible to predict the seepage-stress coupled failure of backfill with defects. The research results can provide a theoretical basis for stability monitoring and failure prediction of backfill in deep water-rich mines in China.