Appraisal of rock IR law and damage precursor: Insight infrared thermogram entropy

• Published in: Infrared physics & technology Vol. 127; p. 104443
• Main Authors: Gao, Qiangqiang, Ma, Liqiang, Liu, Wei, Cao, Kewang, Muhammad Khan, Naseer, Zhao, Zhiyang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2022
• Subjects: Fracture precursors; Infrared radiation (IR); Remote sensing rock mechanics (RSRM); Thermal infrared image entropy; Remote sensing rock mechanics (RSRM); Fracture precursors; Infrared radiation (IR); Thermal infrared image entropy
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/j.infrared.2022.104443

•A new quantitative index of rock infrared radiation is proposed: infrared image entropy (IE).•The relationship between the rock's stress and IE as well as the precursor of rock failure threshold is established.•The mechanism of infrared image entropy change in the rock loading stage is revealed.
During the process of force deformation, the rock will be destabilized and damaged, and a deep understanding of the rock rupture precursors is a crucial foundation for early warning of mine hazards, including mine water inrush and surrounding rock destabilization. This study investigates the properties of infrared radiation (IR) and the precursors of rupture in the process of rock fracture using a novel thermal infrared analysis method called index-infrared image entropy (IE). The IE variation mechanism is discussed together with the frequency histogram of infrared images. The results highlight that IE may be used to characterize the IR information of rock during the pre-peak loading period. The IE value increases rapidly during the pre-peak loading period, then increases slowly and eventually tends to stabilize. Pre-peak stress and IE are correlated using a logarithmic function. The rock enters the plastic stage when the change in IE reaches 2.78, which may be utilized as a precursor threshold of bearing rock failure. At this point, the precursor stress level is 0.93σmax. In addition, abnormal IR histogram changes from a single peak to a double peak form may serve as a crucial precursor to bearing rock failure. The study's findings are useful for mining and geotechnical engineering monitoring and early warning of nearby rock instability and mine water inrush.