Abstract: The aim of this paper is to derive and analyze several parameters of acoustic emission (AE) under the deformation and failure process of rock. These AE experiments of rock failure have been conducted in biaxial loading with the hole rock and some parameters of AE have been obtained. The variation features of the AE energy parameters (including energy rate and cumulative energy), the AE event parameters (including event count rate and cumulative event count), the b-value and the entropy value in loading process have been analyzed systematically. Meanwhile, the AE precursory characteristics of rock failure have been studied, and the variation and precursory characteristics of different AE parameters have also been comparatively analyzed. Furthermore, the suitable AE parameters for predicting rock failure have been explored. The results have shown that the various AE parameters are correspondent to different variation characteristics. The AE energy keeps a small release in the relatively low stress phase, and it increases gradually in the middle stress phase then dramatically in the high stress phase. The number of AE events is few in the low stress phase, and rises rapidly in the middle stress phase and drops greatly in the high stress phase. The b-value decreases with volatility during the most rock loading process and performs an evidently decrease just before the rock failure; while, the entropy value is in the reverse change trend. All the AE parameters have the precursors of rock failure which occur at 82% to 96% of peak stress, while the precursors of the entropy value occur relatively earlier and that of the b-value occur relatively later. Additionally, this study has shown that the precursor of rock failure would be easy to identify with the AE cumulative parameter curve. An integrated analysis of AE multi-parameters will provide an effective and quantitative way to derive the information for precursor of rock failure.

Key words: rock, acoustic emission, multi-parameters, failure, precursor