Abstract: Experiments on acoustic emission (AE) characteristics of complete rock failure process are carried out under uniaxial loading. The stress- strain curve, the relation between AE characteristics and time are obtained. The relation of the time with cumulative AE events, AE energy release rate, and the b-value of the relation between the magnitude and frequency are selected to study the precursory characteristics of rock failure. The results show that during the initial loading phase, AE events are very few and its cumulative number rapidly increases at the late phase of the rock elastic deformation and at the plastic phase; the AE energy keeps a low release rate for a long time during the rock fracturing process but exhibits an evident release just before the rock failure. Before the rock instability failure, b-value will drop quickly, with that of most rock samples reaching the lowest value before the rock failure, These precursory characteristics are significant for the field application of AE monitoring and forecasting technology so as to improve the accuracy of in-situ rock mass monitoring and forecast.

Key words: Rock mechanics, Acoustic emission (AE), Rock failure, b-value, AE energy release rate