Study on the Variation of Infrasound Intensity in Different Frequency Bands before Coal Sample Failure

In order to predict damage of coal samples based on the characteristics of infrasonic wave, acoustic wave test in uniaxial loading process was carried out on coal samples by using coal and rock stress loading device, infrasonic wave acquisition device and acoustic emission acquisition device. The test results were analyzed by wavelet denoising, acoustic emission counts and infrasonic wave energy methods. The analysis results show that: frequency variation of infrasonic wave demonstrated phase characteristics in the process of loading, and it was well consistent with phase characteristics of acoustic emission variation, which proves feasibility of predicting coal sample damage according to variation of infrasonic wave frequency. At the same time, compared with acoustic emission, infrasonic wave frequency is low, which can compensate for shortcomings of coupling contact and fast attenuation of acoustic emission prediction method to a certain extent. A new method for predicting coal sample damage is proposed, which provides guidance for further application of infrasonic wave prediction technology to coal mine disaster prediction.