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Geomechanics and Engineering   Volume 13, Number 1, July 2017, pages 63-77
DOI: https://doi.org/10.12989/gae.2017.13.1.063
 
Characterization of the brittleness of hard rock at different temperatures using uniaxial compression tests
Guoqing Chen, Tianbin Li, Wei Wang, Fan Guo and Hongyu Yin

 
Abstract     [Buy Article]
    The failure mechanism of a deep hard rock tunnel under high geostress and high geothermalactivity is extremely complex. Uniaxial compression tests of granite at different temperatures were conducted. The complete stress-strain curves, mechanical parameters and macroscopic failure types of the rock were analyzed in detail. The brittleness index, which represents the possibility of a severe brittleness hazard, is proposed in this paperby comparing the peak stress and the expansion stress. The results show that the temperature range from 20 to 60°C is able to aggravate the brittle failure of hard rock based on the brittleness index. The closure of internal micro cracks by thermal stress can improve the strength of hard rock and the storage capacity of elastic strain energy. The failure mode ofthe samples changes from shear failure to tensile failure as the temperature increases. In conclusion, the brittle failure mechanism of hard rock under the action of thermal coupling is revealed, and the analysis result offers significant guidance for deep buried tunnels at high temperatures and under high geostress.
 
Key Words
    deep buried tunnel; high geothermal activity; brittle failure; expansion stress
 
Address
(1) Guoqing Chen, Tianbin Li, Wei Wang, Fan Guo, Hongyu Yin:
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, #1 Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, China;
(2) Guoqing Chen:
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China.
 

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