The law of infrared radiation generation and evolution of coal rock fracture under load

In order to study the formation mechanism and evolution law of infrared radiation (IR) of coal-rock. A mathematical model of pressure-IR for coal-rock under loading conditions was developed based on theories such as frictional heat generation and heat conduction. The results indicate that: (1) IR and stress exhibit a one-dimensional quartic function relationship, which is consistent with the strong correlation shown by the experimental data curve. As the loading stress increases, the infrared radiation temperature of the coal-rock surface increases. (2) From the simulation results, it can be seen that the increase in surface temperature of coal-rock is essentially influenced by the heat transfer of internal heat sources. The trend of temperature fluctuations is similar for both, with both increasing with ambient temperature and loading rate. And this characteristic change is independent of external loading factors. (3) The IR temperature varies in stages under different loading conditions. In addition, the surface temperature of the coal-rock before fracturing is affected by the frictional heat generation between cracks, resulting in an overall upward trend. When it is about to break, a precursor to the fracture appears. The final IR on the surface of coal-rock increased by 0.04–0.13 °C, which is consistent with the simulation results. It is consistent with the simulation results and reveals the evolution law of IR. The results of this work provide theoretical evidence for the prediction of dynamical disasters in coal and rocks.