Experimental Study on the Change Features of Infrasonic Waves in Coal Sample Loading

Abstract

In order to study the change features of infrasonic waves in coal sample loading, we collect coal samples from the research area, conduct both lab test and theoretic analysis, and based on filtered and de-noised signals, establish the characteristic parameter of infrasonic waves – relative energy, and analyze the changes in the energy parameter of infrasonic waves in the loading process. The analysis shows: in the loading process, the energy of infrasonic waves changes in stages, including the slow increase, rapid increase towards the peak and slow decrease stages, which are consistent with the deformation stages of coal samples, and when the coal samples enter the plastic deformation stage from the elastic deformation stage, the infrasonic waves show an obvious abnormal change. Therefore, we can predict the deformation and failures of coal samples according to the changes in the energy of infrasonic waves. At the same time, due to advantages like non-coupled contact and small attenuation, the infrasonic wave prediction method is very useful in the coal sample failure prediction. This is of great significance to improving the accuracy of coal sample failure prediction and reducing coal mine accidents.