Infrared radiation quantification of rock damage and its constitutive modeling under loading

The root cause of the infrared radiation (IR) change in rock is the failure of microelements during its evolution. However, the quantified relationship between the two parameters remains unclear. This paper, therefore, pre-sents a quantification approach to investigate the internal damage evolution of loading rock through the surface IR. Multiparameter observation experiments were conducted primarily in coal rock samples. The change in related parameters within the rock sample during the evolution of the damage was recorded. The IR noise from the reference (unloaded) samples was taken as the threshold of the sudden change in the IR temperature. Thus, the noise signal and the sudden change in IR temperature were separated through these threshold values. On this basis, a quantitative index of infrared radiation, the IR counts was adopted. It was found that there was a synchronous sudden change between the IR and Acoustic ringing counts. According to the occurrence of sudden change in the IR counts and the differential infrared radiant thermal image sequence at the corresponding time, the damaged area of the rock can be accurately determined. Taking the IR counts as the characterization parameter of the rock damage variable, the quantitative characterization method of the evolution of coal-rock damage by IR and the stress-strain constitutive model was established. The IR calculated stress (sigma(IR)) can reflect the failure process of rock transition from the linear elastic to the plastic deformation stage.

Automated summary

This paper presents a quantification approach to investigate the internal damage evolution of loading rock through surface infrared observation. By analyzing the changes in infrared radiation and acoustic counts, the damaged area of the rock can be accurately determined, and a quantitative method for characterizing the evolution of rock damage is established.