Infrared radiation response mechanism of sandstone during loading and fracture process

Rock damage and fracture are the fundamental causes of coal mine dynamic disasters such as coal and gas outbursts, rock bursts, and mine water inrush. It is also one of the basic and common scientific problems in the field of rock engineering. Therefore, the reliable precursor information of rock damage and fracture process can be determined for the effective monitoring of the early warning of coal mine dynamic disaster, and early warning of surrounding rock fracture and seepage (water inrush) in mines. In this regard, the researcher failed to describe the mechanism of infrared radiation characteristics for the determination of rock failure precursors quantitatively. Further, the qualitative analysis of the infrared radiation mechanism restricts the use of infrared radiation to characterize the internal damage evolution and permeability characteristics of rocks. Therefore, in this paper, the equivalent plastic strain difference of sandstone is defined based on the plastic strain energy and deformation work conversion equation. The frictional heat effect of loaded sandstone is clarified. According to the Euclidean distance between the plastic zone location and the crack tip, the temperature source density function of the crack plastic zone is characterized. Based on the Fourier law of heat conduction, the thermal effect of crack propagation is deduced and analyzed, and the mathematical model of the infrared radiation response mechanism in the process of sandstone loading and fracture is established. Based on this model, the heat conduction range of sandstone fracture under biaxial loading is determined through the secondary development of finite element software, and the average infrared radiation temperature in the local high-temperature region of loaded sandstone is predicted. The findings of this research can provide a theoretical and experimental foundation for detecting rock failure for the safe and efficient execution of underground engineering projects e.g. mines, tunnels, etc.