Water Saturation Effects on Thermal Infrared Radiation Features of Rock Materials During Deformation and Fracturing
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ORIGINAL PAPER
Water Saturation Effects on Thermal Infrared Radiation Features of Rock Materials During Deformation and Fracturing Xin Cai1 · Zilong Zhou1 · Lihai Tan1 · Haizhi Zang1,2 · Zhengyang Song3 Received: 25 November 2019 / Accepted: 19 June 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract This paper aims to investigate the water saturation effects on the thermal infrared radiation (IRR) characteristics of rock materials during deformation and fracturing processes. Three kinds of rocks, namely sandstone, granite, and marble, were adopted for tests. Uniaxial compression tests were carried out on oven-dried and water-saturated rock samples. The evolution of IRR temperature on rock surface was monitored and recorded with the aid of an infrared thermographic camera. Test results show that the IRR temperature of saturated samples is apparently higher than that of dry ones subjected to the same axial stress. After water saturation, the heating rate in elastic deformation phase, the IRR temperature increment at peak stress, and the IRR temperature on the new-formed fracture surface have a significant growth compared to dry condition. These indicate that the presence of water facilitates the release of thermal energy. The sensitivities of the heating rates in elastic deformation phase to water saturation are very distinct for the three rocks. This is possibly resulted from the mineral composition of rock types, especially the proportion of calcite and swelling clay minerals. The IRR temperature increment at peak stress for rock not only depends on the moisture condition, but is also relevant to the uniaxial compressive strength. Keyword Thermal infrared radiation · Water saturation · Average infrared radiation temperature · Coupling thermal-elastic effect · Rock fracture Abbreviations IRR Infrared radiation AIRT Average infrared radiation temperature △T Variation in average infrared radiation temperature ZOI Zone of interest AE Acoustic emission UCS Uniaxial compressive strength We Radiant energy intensity 𝜀 The emissivity of the object * Xin Cai [email protected] * Zilong Zhou [email protected] 1
School of Resources and Safety Engineering, Central South University, Changsha 410010, China
2
ARC Centre of Excellence for Geotechnical Science and Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan 2308, Australia
3
Geotechnical Institute, TU Bergakademie Freiberg, Gustav‑Zeuner‑Straβe 1, 09599 Freiberg, Germany
𝛼 Stefan–Boltzmann constant T Absolute infrared radiation temperature 𝜎 Uniaxial stress △Tf AIRT increment at peak stress △Tmax The maximum temperature increment
1 Introduction Every object exposed to a temperature above absolute zero will emit electromagnetic radiation with a large range of wave lengths (Fig. 1), such as radiofrequency radiation, microwave radiation, infrared radiation (IRR), and light radiation (Brady and Rowell 1986; Martelli et al. 1989; Wu et al. 2000). Among them, the IRR waves fall i
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