An Experimental Study of Effect of High Temperature on the Permeability Evolution and Failure Response of Granite Under Triaxial Compression

Sheng Qi Yang, Wen Ling Tian, Derek Elsworth, Jian Guo Wang, Li Feng Fan

Research output: Contribution to journalArticle

Abstract

Granite is a viable host for deep nuclear waste disposal because its low permeability and high strength enable the stable and safe operation of the repository. We examined the evolution of the permeability and triaxial mechanical behaviour of granite after high-temperature treatment. First, the effect of the high temperature on the physical behaviour and permeability evolution of granite was analysed in detail. The mass, P-wave velocity, and thermal conductivity of granite decrease, but the volume increases with increasing temperature. The permeability of intact granite increases by four orders of magnitude as the cycled temperature increases from 25 to 800 °C. Subsequently, the effect of high temperature on the triaxial deformation and acoustic emission (AE) behaviour of granite was investigated. Under uniaxial compression at T ≤ 300 °C, the stress decreases before the peak strength is reached, corresponding to a significant AE event, which is due to the development of multiple splitting tensile fractures along the loading direction. At T ≥ 450 °C, AE event is observed once a minor stress is applied, which results from failure is controlled by thermally induced cracks. However, under triaxial compression, the temperature has little effect on the AE characteristics. The granite fails along the shear fracture plane, which becomes wider with increasing confining pressure. At T ≥ 600 °C, it is easier to form intragranular cracks and the stress quickly decreases after the peak strength is reached. The shear plane is smoother under high confining pressure. Third, the effect of high temperature on the peak strength and crack damage threshold of granite was further analysed. Generally, under uniaxial compression, the peak strength and crack damage threshold first remain relatively constant at T ≤ 300 °C, begin to decrease at T = 450 °C, and decrease more rapidly at T = 600 °C. The confining pressure notably reduces the effect of the temperature on the peak strength and crack damage threshold. Finally, the effect and mechanism of high temperature on the triaxial strength parameters of granite were further discussed. At T ≤ 300 °C, thermally induced cracks are not notable and the temperature has little effect on the strength. At 450 °C≤ T ≤ 600 °C, thermally induced cracks are more notable and the temperature has a significant effect on the strength behaviour. Because of the thermal stress released by thermal macrocrack formation, the continuous increase in the temperature has little impact on strength.

Original languageEnglish (US)
JournalRock Mechanics and Rock Engineering
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

Granite
Compaction
experimental study
granite
compression
permeability
crack
acoustic emission
Cracks
Acoustic emissions
confining pressure
Temperature
temperature
damage
effect
thermal conductivity
repository
waste disposal
radioactive waste
P-wave

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Geotechnical Engineering and Engineering Geology
  • Geology

Cite this

@article{d9e7cc394602442087d5397327f968e0,
title = "An Experimental Study of Effect of High Temperature on the Permeability Evolution and Failure Response of Granite Under Triaxial Compression",
abstract = "Granite is a viable host for deep nuclear waste disposal because its low permeability and high strength enable the stable and safe operation of the repository. We examined the evolution of the permeability and triaxial mechanical behaviour of granite after high-temperature treatment. First, the effect of the high temperature on the physical behaviour and permeability evolution of granite was analysed in detail. The mass, P-wave velocity, and thermal conductivity of granite decrease, but the volume increases with increasing temperature. The permeability of intact granite increases by four orders of magnitude as the cycled temperature increases from 25 to 800 °C. Subsequently, the effect of high temperature on the triaxial deformation and acoustic emission (AE) behaviour of granite was investigated. Under uniaxial compression at T ≤ 300 °C, the stress decreases before the peak strength is reached, corresponding to a significant AE event, which is due to the development of multiple splitting tensile fractures along the loading direction. At T ≥ 450 °C, AE event is observed once a minor stress is applied, which results from failure is controlled by thermally induced cracks. However, under triaxial compression, the temperature has little effect on the AE characteristics. The granite fails along the shear fracture plane, which becomes wider with increasing confining pressure. At T ≥ 600 °C, it is easier to form intragranular cracks and the stress quickly decreases after the peak strength is reached. The shear plane is smoother under high confining pressure. Third, the effect of high temperature on the peak strength and crack damage threshold of granite was further analysed. Generally, under uniaxial compression, the peak strength and crack damage threshold first remain relatively constant at T ≤ 300 °C, begin to decrease at T = 450 °C, and decrease more rapidly at T = 600 °C. The confining pressure notably reduces the effect of the temperature on the peak strength and crack damage threshold. Finally, the effect and mechanism of high temperature on the triaxial strength parameters of granite were further discussed. At T ≤ 300 °C, thermally induced cracks are not notable and the temperature has little effect on the strength. At 450 °C≤ T ≤ 600 °C, thermally induced cracks are more notable and the temperature has a significant effect on the strength behaviour. Because of the thermal stress released by thermal macrocrack formation, the continuous increase in the temperature has little impact on strength.",
author = "Yang, {Sheng Qi} and Tian, {Wen Ling} and Derek Elsworth and Wang, {Jian Guo} and Fan, {Li Feng}",
year = "2019",
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language = "English (US)",
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An Experimental Study of Effect of High Temperature on the Permeability Evolution and Failure Response of Granite Under Triaxial Compression. / Yang, Sheng Qi; Tian, Wen Ling; Elsworth, Derek; Wang, Jian Guo; Fan, Li Feng.

In: Rock Mechanics and Rock Engineering, 01.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

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AU - Yang, Sheng Qi

AU - Tian, Wen Ling

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AU - Wang, Jian Guo

AU - Fan, Li Feng

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Granite is a viable host for deep nuclear waste disposal because its low permeability and high strength enable the stable and safe operation of the repository. We examined the evolution of the permeability and triaxial mechanical behaviour of granite after high-temperature treatment. First, the effect of the high temperature on the physical behaviour and permeability evolution of granite was analysed in detail. The mass, P-wave velocity, and thermal conductivity of granite decrease, but the volume increases with increasing temperature. The permeability of intact granite increases by four orders of magnitude as the cycled temperature increases from 25 to 800 °C. Subsequently, the effect of high temperature on the triaxial deformation and acoustic emission (AE) behaviour of granite was investigated. Under uniaxial compression at T ≤ 300 °C, the stress decreases before the peak strength is reached, corresponding to a significant AE event, which is due to the development of multiple splitting tensile fractures along the loading direction. At T ≥ 450 °C, AE event is observed once a minor stress is applied, which results from failure is controlled by thermally induced cracks. However, under triaxial compression, the temperature has little effect on the AE characteristics. The granite fails along the shear fracture plane, which becomes wider with increasing confining pressure. At T ≥ 600 °C, it is easier to form intragranular cracks and the stress quickly decreases after the peak strength is reached. The shear plane is smoother under high confining pressure. Third, the effect of high temperature on the peak strength and crack damage threshold of granite was further analysed. Generally, under uniaxial compression, the peak strength and crack damage threshold first remain relatively constant at T ≤ 300 °C, begin to decrease at T = 450 °C, and decrease more rapidly at T = 600 °C. The confining pressure notably reduces the effect of the temperature on the peak strength and crack damage threshold. Finally, the effect and mechanism of high temperature on the triaxial strength parameters of granite were further discussed. At T ≤ 300 °C, thermally induced cracks are not notable and the temperature has little effect on the strength. At 450 °C≤ T ≤ 600 °C, thermally induced cracks are more notable and the temperature has a significant effect on the strength behaviour. Because of the thermal stress released by thermal macrocrack formation, the continuous increase in the temperature has little impact on strength.

AB - Granite is a viable host for deep nuclear waste disposal because its low permeability and high strength enable the stable and safe operation of the repository. We examined the evolution of the permeability and triaxial mechanical behaviour of granite after high-temperature treatment. First, the effect of the high temperature on the physical behaviour and permeability evolution of granite was analysed in detail. The mass, P-wave velocity, and thermal conductivity of granite decrease, but the volume increases with increasing temperature. The permeability of intact granite increases by four orders of magnitude as the cycled temperature increases from 25 to 800 °C. Subsequently, the effect of high temperature on the triaxial deformation and acoustic emission (AE) behaviour of granite was investigated. Under uniaxial compression at T ≤ 300 °C, the stress decreases before the peak strength is reached, corresponding to a significant AE event, which is due to the development of multiple splitting tensile fractures along the loading direction. At T ≥ 450 °C, AE event is observed once a minor stress is applied, which results from failure is controlled by thermally induced cracks. However, under triaxial compression, the temperature has little effect on the AE characteristics. The granite fails along the shear fracture plane, which becomes wider with increasing confining pressure. At T ≥ 600 °C, it is easier to form intragranular cracks and the stress quickly decreases after the peak strength is reached. The shear plane is smoother under high confining pressure. Third, the effect of high temperature on the peak strength and crack damage threshold of granite was further analysed. Generally, under uniaxial compression, the peak strength and crack damage threshold first remain relatively constant at T ≤ 300 °C, begin to decrease at T = 450 °C, and decrease more rapidly at T = 600 °C. The confining pressure notably reduces the effect of the temperature on the peak strength and crack damage threshold. Finally, the effect and mechanism of high temperature on the triaxial strength parameters of granite were further discussed. At T ≤ 300 °C, thermally induced cracks are not notable and the temperature has little effect on the strength. At 450 °C≤ T ≤ 600 °C, thermally induced cracks are more notable and the temperature has a significant effect on the strength behaviour. Because of the thermal stress released by thermal macrocrack formation, the continuous increase in the temperature has little impact on strength.

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