Experimental study of fractal dimension of AE serials of different rocks under uniaxial compression

Fractal dimension of AE(acoustic emission) serials of different types of rocks was investigated by uniaxial compression test.The complete stress-strain curves,the AE characteristics and the fracture patterns were obtained.The rupture instability specimens of destruction were observed;and the load change relationships of failure process were analyzed.Different mechanical properties,the AE sequence of time domain features and fractal feature of different rocks were researched emphatically.The results show that the AE rates ad AE energy rates can be very good to describe the collapse of the rock masses.The correlation dimension of the AE rates and AE energy rates during the progressive failure process has a strong characteristic of fractal feathers.The fractal dimension of AE sequences reflected the statistical evolution of the initiation and propagation of the microcracks in the rocks.The fractal dimension for all the specimens decreased when the loading stress increased.The evolutions of the fractal dimension of AE during failure can be divided into a mode for rocks.The fractal dimension for a mode of "fluctuation→gradual descending".The descent of the fractal dimension can be regarded as the precursor information to predict the collapse of the rock masses.