Measuring the damage evolution of granite under different quasi-static load rates through acoustic emission time-frequency characteristics and moment tensor analysis

The time-frequency characteristics of the AE signal under tensile failure conditions and their correlation with the AE crack moment tensor were measured and analyzed. The results show that when reaching the threshold of tensile stress, there is a noteworthy increase in the rate of AE events, implying a sudden surge in failure activity. The distribution of frequency bands centered around the centroid mainly spans from 125 kHz to 375 kHz. Applying fractal analysis to the moving-average-processed frequency domain signals unveils that the fractal dimension reaches its peak value during the σd-σf period. Starting from the initiation of microcracks to eventual failure, the probability density range linked to the primary frequency band precisely identifies the underlying mechanisms of rock damage. The Gaussian Mixture Model (GMM) surpasses the k-Means algorithm in identifying rock damage mechanisms in the context of splitting conditions. The moment tensor theory proficiently characterizes the tensile rupture is predominant.