Quantitative Analysis of Infrared Thermal Images in Rock Fractures Based on Multi-Fractal Theory

Abstract

Rock disasters caused by rock fractures seriously threaten the safe and sustainable mining of deep coal resources. The infrared thermal imaging of rock fractures has a non-uniform distribution. This is important information for the monitoring and early warning of rock mass instability. In this paper, the multi-fractal theory was introduced to analyze the infrared thermal image obtained from the uniaxial loading of sandstone, which is expected to provide quantitative indicators for the infrared monitoring of rock failure. The results show that the multi-fractal parameters Δα (non-uniformity of temperature) and Δf (frequency diversity of minimum and maximum temperature) can be used to describe the distribution of the thermal field; they are sensitive to the rock macro fracture. Both Δα and Δf are constant during the initial loading stage. When the samples yield and there is a failure in the later stage of loading, the Δα and Δf change abruptly. The sudden change in Δα and Δf can be regarded as the precursor to rock failure. The research results preliminarily show the feasibility and potential of multi-fractal analysis in rock mass disaster monitoring and early warning.

Multifractal Analysis for the Acoustic Emission Energy Dissipation of Shale after Long-Term Immersion in Fracturing Fluids with Various pH

“…Furthermore, multifractal theory can also be employed for analyzing infrared thermal images to provide quantitative indices for infrared monitoring of rock failure events. 59 AE data can be utilized to analyze fractal properties of rocks, 29 patterns of rock failure, 60 fracture evolution processes, 61,62 as well as early warning signs indicating instability precursors. 63 By examining multiple characteristics within AE time series, we gain insights into the dynamic nonlinear evolution process of rock fractures.…”

“…Applying multifractal theory for analyzing CT scan images , and NMR spectra is an effective means for quantitatively evaluating pore distribution and fracture structure in complex reservoirs. Furthermore, multifractal theory can also be employed for analyzing infrared thermal images to provide quantitative indices for infrared monitoring of rock failure events . AE data can be utilized to analyze fractal properties of rocks, patterns of rock failure, fracture evolution processes, , as well as early warning signs indicating instability precursors .…”

Some Thoughts about Infrared Radiation Response Characteristics during Loading of Sandstone Samples

“…Many researchers have carried out infrared radiation experiments [8][9][10] on various geotechnical materials. These studies have explored the relationships between the temporal-spatial distribution characteristics of infrared radiation and the fracturing process of coal/rocks [11][12][13]. For example, Wu et al found that the average infrared radiation temperature (AIRT) can be used as a quantitative indicator to characterize the stress distribution of coal and rock during compression [14].…”