Study on Acoustic Emission Characteristics and Failure Prediction of Post-High-Temperature Granite

Abstract In an attempt to study the acoustic emission (AE) characteristics of granite specimens (25°C~600°C) during high-temperature deformation, the uniaxial compression and general triaxial compression tests were carried out. The AE signals were collected simultaneously, following which the AE signals were processed to predict rock failure. The study makes some interesting conclusions. In the uniaxial compression test, AE activity is found to be more active during the postpeak stress phase. In the triaxial compression test, AE activity is found to be more active during the postpeak stress phase. The AE energy and the cumulative energy under uniaxial compression are much larger than the triaxial compression at the failure moment of the granite specimen after the same heat treatment. As the heat-treatment temperature increases, the peak AE energy decreases, but the cumulative AE energy decreases first and then increases. The failure of granite was predicted by AE signal processing, and good prediction results were obtained for different experimental conditions and the different preset failure time tf. The time at which the forecast point appears is usually close to the time at which the rock specimen enters the plastic deformation phase. The value of the parameter tf impacts the curve shape and prediction duration without affecting the occurrence of the forecast point. In addition, the shape of curve changes stepwise as the tf changes.