Theoretical analysis of characteristics of acoustic emission in rock failure based on statistical damage mechanics

Abstract

Based on statistical damage mechanics, the constitutive model of a rock under three-dimensional stress was established by the law that the statistical strength of rock micro-element obeys Weibull distribution. The acoustic emission (AE) evolution model of rock failure was put forward according to the view that rock damage and AE were consistent. Moreover, in the failure process of rock under three-dimensional stress, the change in relationship between stress condition parameter and the characteristic parameters of AE, such as the event number and its change rate, were studied. Also, the rock AE characteristic under uniaxial compression was analyzed in theory and verified with examples. The results indicate that the cumulative event number and change rate of AE in rock failure are determined by stress state parameter F. Along with the gradual increase of F, first the cumulative event number increases gradually, then rapidly, and then slowly after the stress peak. The form of change rate of an event by increasing F is consistent with the distribution form of rock micro-element strength. The model explained the phenomenon that a relatively quiet period of AE appears before rock rupture that is observed by many researchers in experiments. Verification examples indicate that the AE evolution model is consistent with the test results, so the model is reasonable and correct.