IDENTIFICATION OF THE PREDICTIVE INFORMATION BEFORE ROCKMASS FAILURE BASED ON b-VALUE OF AE EVENTS AND ITS DEFICIENCY

摘要

The multi-channels acoustic emission acquiring system was employed to record the AE events in failure process of rock specimens with different lithology. Dynamic curves of AE b-value were gained by the scan-calculating method. In the early and middle phases of loading, the AE A-value generally shows ascending trend. But, there were waves with different scales and times at b-value curves before they reach peak value. Finally, the b-value descends quickly when the specimen approaches total failure. Consequently, the descending of b-value did not present the failure of rock, only AE frequency and magnitude factors could not reflect the structure status inside rock accurately, of course it could not forecast the rock dynamic disaster reliably. The mechanism of the rock dynamic failures is greatly complicated. For forecasting the rock failure more accurately, the information included in the AE signals need to be more excavated, and should conduct comprehensive analysis and investigation combined with the factors of mechanical status.