Influence of the loading rate on the evolution characteristics of AE and MS signals during granite failure

Abstract

To explore precursor rock failure information near a tunnel excavation boundary under different excavation rates, biaxial compression tests of granite failure under different loading rates were conducted, and the acoustic emission (AE) and microseismic (MS) signals produced by granite failure were monitored and analyzed. The results indicate that loading rate has an important effect on the evolution of AE and MS signal characteristic parameters. Hence, a multi-parameter rock failure warning method based on AE and MS according to different loading rates was proposed, which provides the scientific basis for safety warning of deep engineering. A damage evolution equation based on AE and MS is established to quantitatively describe the damage process of granite under different loading rates. Moreover, it is confirmed that there are vast variations in the sensitivity of AE and MS signals to the formation of cracks of different sizes. Therefore, combining AE and MS signals to monitor the granite failure process will help to reveal the mechanism of granite failure and improve the accuracy of granite failure prediction.