Study on the effects of temperature and immersion on the acoustic emission and electromagnetic radiation signals of coal rock damage under load

As the mining depth increases year by year, the geological environment of the coal seam becomes more complex. Coal rocks are vulnerable to damage from high temperature, immersion, high ground stress and other factors. This study is aimed at realizing the monitoring and early warning of coal rock dynamic disasters in complex environments such as high temperature and immersion. Firstly, mechanical properties of coal rocks after high temperature and immersion treatment were tested through experiments. It was found that both high temperature and immersion can cause mechanical damage to coal rock. In addition, the acoustic emission (AE) and electromagnetic radiation (EMR) signals generated by coal rock samples during failure were collected in real time. The following conclusions were drawn: All these signals are closely related to the damage degree of coal rock. The AE and EMR signals generated by coal rock under load after different temperature treatments were different, and their intensity decrease after immersion treatment. Furthermore, the damage of coal samples caused by high temperature and immersion was explored through quantitative analysis, and the evolution law of crack propagation during coal rock failure was discussed. The mechanical properties of coal rock after the damage of high temperature and immersion and the mechanisms of AE and EMR signal generation and variation during deformation and failure were revealed. This study provides theoretical guidance for the monitoring of coal rock dynamic disasters. •he change pattern of acoustic emission and electromagnetic radiation from coal rocks after high temperature and waterlogging are revealed.•Quantitative analysis of damage evolution and nonlinear characteristics of acoustic emission signals of coal and rock under load failure.•The differences in failure modes of coal and rock caused by high temperature and immersion.