An experimental study on infrared radiation and acoustic emission characteristics during crack evolution process of loading rock

During the stress-induced rock failure process, anomalies in the Infrared Radiation (IR) can be observed. To study the response relationships between rock IR temperature and spatial-temporal evolution process of cracks in sandstone, the IR and Acoustic Emission (AE) were both measured during uniaxial compression. The multi frames accumulation average technology and background thermal noise correction method were used to correct the IR temperature. According to the AE results, the temporal evolution process of cracks was divided into six stages: initial crack closure, linear elastic deformation, micro-crack development, macro-crack initiation, macro-crack propagation, and macro-crack coalescence. It was found that the changing rate of the Average Infrared Radiation Temperature (AIRT) changed with the crack evolution stage changed, which could be regarded as a basis for dividing the evolution stages of rock cracks using IR. The accumulated energy density map of AE events was used to analyze the spatial distribution characteristics of cracks and determine the Low Damage Area (LDA) and High Damage Area (HDA) of the rock samples. It was found that the AIRT variations were consistent between LDA and HDA during the entire loading process. However, since the stage of micro-cracks development, the difference value in AIRT between LDA and HDA gradually increased with time. The research results can provide a reference for the study of the rock crack evolution process with the surface IR information and are helpful to the early warning of rock failure.

Automated summary

The study found that the infrared radiation temperature can be used to analyze the evolution stages and spatial distribution characteristics of rock cracks, which is helpful for early warning of rock failure.