Abstract:Through the acoustic emission(AE) experiments in the process of rock failure,the strength fractal model of acoustic emission in the process of rock failure is established. The AE fractal features of all stress levels in the whole rock failure and the changing rules of fractal value, which varies from time to time,are studied. The results show that,in the initial stage of loading,the AE fractal value of rock samples is unsteady. But from the viewpoint of the general changing trend,the fractal value in this period still remains greater. In the middle and later stage,the fractal value has obvious regularity, changing from great to small. The fractal value reaches to the minimum at the critical point of sample failure. Since it is difficult to confirm the minimum fractal value (critical value) in practical application,it is found that the continually declining fractal value is the premonitory feature of rock failure. Consequently,it provides theoretical basis and means for in-situ rock mass monitoring and forecast by acoustic emission parameter.