An experiment on temperature variations in sandstone during biaxial loading

Chen, Shunyun; Liu, Peixun; Guo, Yanshuang; Liu, Liqiang; Ma, Jin

doi:10.1016/j.pce.2014.10.006

Cited by 23 publications

(10 citation statements)

References 26 publications

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“…In our experiment, diffuse wave frequencies range from 300 kHz to 900 kHz, the associated wavelengths are equivalent to the mesoscopic scale of brittle rocks (grain size), leading to strong multiple scattering at grain boundaries. With the applied forces, the opening and closing of grain boundaries and grain contacts emit thermal infrared radiations (Chen et al, ; Wu et al, ). In other words, velocity and infrared radiation depend on microcracks opening/closing induced by stress.…”

Section: Discussionmentioning

confidence: 99%

Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

et al. 2018

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Diffuse acoustic or seismic waves are highly sensitive to detect changes of mechanical properties in heterogeneous geological materials. In particular, thanks to acoustoelasticity, we can quantify stress changes by tracking acoustic or seismic relative velocity changes in the material at test. In this paper, we report on a small‐scale laboratory application of an innovative time‐lapse tomography technique named Locadiff to image spatiotemporal mechanical changes on a granite sample under biaxial loading, using diffuse waves at ultrasonic frequencies (300 kHz to 900 kHz). We demonstrate the ability of the method to image reversible stress evolution and deformation process, together with the development of reversible and irreversible localized microdamage in the specimen at an early stage. Using full‐field infrared thermography, we visualize stress‐induced temperature changes and validate stress images obtained from diffuse ultrasound. We demonstrate that the inversion with a good resolution can be achieved with only a limited number of receivers distributed around a single source, all located at the free surface of the specimen. This small‐scale experiment is a proof of concept for frictional earthquake‐like failure (e.g., stick‐slip) research at laboratory scale as well as large‐scale seismic applications, potentially including active fault monitoring.

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Section: Discussionmentioning

confidence: 99%

Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

et al. 2018

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“…During the experiment, the TIR from the rock surface is affected by the atmosphere, the sun, and stress, etc. In terms of frequency, there are three main, significant components [17][18][19]: (1) high frequency: the frequency of TIR changes in this component is larger than that of the stress, which is mainly related to the fluctuant change of the environment and the instrumental noise; (2) middle frequency: the frequency of TIR changes is consistent with that of the stress, which indicates that the TIR changes are induced by stress; (3) low frequency: the frequency of TIR changes is smaller than that of the stress, and the TIR changes are mainly in response to the continuous and slow changes in the environment in a relatively long period [53,54]. Considering the above frequency characteristics, the ∆AIRT signals during rock loading can be divided into three components, as shown in Equation 5:…”

Section: Wavelet Analysismentioning

confidence: 98%

“…where ∆T is the temperature change (K), ∆σ is the change in the sum of the principal stress (MPa), α is the thermal expansion coefficient for solid material ( • C −1 ), ρ is the density (kg/m 3 ), C p is the specific heat capacity (J/kg• • C), and T is the absolute temperature of a unit object (K). According to the literature [47,54], the values of thermal parameters for sandstone are as follows: α = 7.8 × 10 −6 • C −1 , ρ = 2230 kg/m 3 , and C p = 710 J/kg• • C. Those for granite are: α = 7.5 × 10 −6 • C −1 , ρ = 2640 kg/m 3 , and C p = 820 J/kg• • C. According to Equation (6), when the initial temperature of the granite was 20.3 • C, and the main stress variation was 60 MPa, the temperature increase can be calculated as 0.061 K. For sandstone, when the main stress variation was 35 Mpa, the temperature increased by 0.051 K. The increasing rate of ∆AIRT mid for sandstone is higher than that for granite. Figures 4a and 6a show that the amplitude of ambient temperature change was about 0.2 K, and that the amplitude of ∆AIRT mid was only 15-40% of the ambient temperature.…”

Section: The Relationship Between the Change In The Tir And Stressmentioning

confidence: 99%

Experimental Study of Extracting Weak Infrared Signals of Rock Induced by Cyclic Loading under the Strong Interference Background

Huang

Liu

et al. 2018

Applied Sciences

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To understand the possibility of monitoring the crustal stress and tectonic activities via satellite remote sensing technology, an experimental study focused on the thermal infrared variation was performed for cyclic loaded rock in the outdoor condition with two types of strong interference background. The stress-induced infrared radiation was extracted using wavelet analysis. The results showed that due to the significant effect of the ambient temperature, the weak stress-induced infrared signal was indistinguishable from the original infrared radiation. However, after wavelet decomposition, the infrared radiation concurrent with the change in stress became clear, and the correlation coefficient with the stress increased significantly with the value of 0.91 after decomposition. Additionally, the amplitude of the extracted stress-induced infrared signal was close to the theoretical result, indicating that the wavelet analysis method can extract the weak infrared signals induced by cyclic loading in the background of strong interference to some degree. The results provide an experimental basis and ideas for monitoring crustal stress and tectonic activities using thermal infrared remote sensing.

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“…Chen et al . [] analyzed the principal stress‐strain variation and temperature response in detail based on thermodynamics, elastic strain theory, and experiments on both ideal material and rock. Their results imply that temperature change is only related to the volume strain variation and that pure shear deformation does not contribute to temperature variation.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Consequently, the temperature response properties associated with stress changes in rocks are key to improving understanding of temperature anomalies. Some theoretical and experimental studies have been conducted on the thermoelastic response of rocks and the thermodynamics of minerals [Waldbaum, 1971;Richter and Simmons, 1974;Wong and Brace, 1979;McTigue, 1986;Wong et al, 1987;Wong et al, 1988;Stixrude and Lithgow-Bertelloni, 2005;Ma et al, 2007;Mosenfelder et al, 2007;Chen et al, 2009;Ma et al, 2012;Chen et al, 2015]; however, it is still very difficult to carry out experiments under adiabatic conditions because there must be heat exchange when the loading/ unloading system is open to the air.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of the temperature response to stress changes of rocks

et al. 2017

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The temperature response to stress changes of rocks is key to understanding temperature anomalies in geoscience phenomena such as earthquakes. We developed a new hydrostatic compression system in which the rock specimen center can achieve adiabatic conditions during the first ~10 s following rapid loading or unloading and systematically measured several representative sedimentary, igneous, and metamorphic rocks sampled from two seismogenic zones (the Longmenshan Fault Zone in Sichuan and the Chelungpu Fault Zone (TCDP Hole‐A) in Taiwan) and several quarries worldwide. We built a finite element model of heat conduction to confirm the measured results of temperature response to stress changes of rocks. The results show that (1) the adiabatic pressure derivative of the temperature (β) for most crustal rocks is ~1.5 mK/MPa to 6.2 mK/MPa, (2) the temperature response to stress of sedimentary rocks (~3.5–6.2 mK/MPa) is larger than that of igneous and metamorphic rocks (~2.5–3.2 mK/MPa), and (3) there is good linear correlation between β (in mK/MPa) and the bulk modulus K (in GPa): β = (−0.068K + 5.69) ± 0.4, R2 = 0.85. This empirical equation will be very useful for estimating the distribution of β in the crust, because K can be calculated when profiles of crustal density (ρ) and elastic wave velocities (Vp, Vs) are obtained from gravity surveys and seismic exploration.

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An experiment on temperature variations in sandstone during biaxial loading

Cited by 23 publications

References 26 publications

Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

Experimental Study of Extracting Weak Infrared Signals of Rock Induced by Cyclic Loading under the Strong Interference Background

Experimental and numerical investigation of the temperature response to stress changes of rocks

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