Infrared radiation characteristics of heterogeneous granite fracture under compression

Infrared thermal imaging monitoring technology currently cannot accurately characterize the changes in rock internal structural damage, which remains a scientific problem requiring further investigation in modern rock mechanics. To address this issue, this paper takes granite as the research object. The indoor infrared thermal imaging monitoring of granite under uniaxial loading conditions and numerical simulation experiments of uniaxial compression in heterogeneous granite using the finite difference software FLAC3D were conducted. The quantitative relationship between surface damage variables and internal damage variables at different loading stages of granite is established. Specifically, the relationship is exponential during the plastic deformation stage, while in the failure stage, the relationship becomes parabolic, characterized by a simultaneous surge phenomenon in both types of damage. Furthermore, the quantitative relationship between infrared radiation temperature and principal stress is established, revealing that the correlation between infrared radiation temperature and principal stress is a positive linear relationship with a linear correlation coefficient exceeding 0.95. Finally, this research combines numerical simulations of the rock fracture process with infrared thermal imaging monitoring. On this basis, a new interactive method that integrates infrared thermal imaging and numerical simulation for rock fracture analysis is proposed.