岩土工程学报2026，Vol.48Issue(1)：33-44,12.DOI:10.11779/CJGE20240429
高温后花岗岩三轴压缩条件下力学特性试验研究
Experimental investigation on mechanical behaviors of granite specimens after thermal treatment under conventional triaxial compression
摘要
Abstract
With the further development of high-temperature rock engineering,it is necessary to accurately reveal the influence of high temperature and high pressure on the changing mechanisms of physical and mechanical properties of reservoir rocks to analyze the stability of high-temperature rock engineering reservoirs and improve resource extraction efficiency.Based on the conventional triaxial compression tests of granite after high temperature ranging from 20 to 600℃under different confining pressures,complete stress-stain curves of granite under conventional triaxial compression are analyzed and the influence of temperature and pressure on the deformation and strength characteristic and failure mode is discussed.Meanwhile,their changing mechanisms of mechanical properties of granite after exposure to various temperatures are revealed through optical microscopy observations.The test results show that:(1)The triaxial compressive strength and elastic modulus of granite after high temperature gradually decrease with temperature,and increase with confining pressure.Compared with room temperature,the uniaxial compressive strength and elastic modulus at 600℃decreased by 56.47%and 54.63%,respectively,while under 60 MPa conditions,the triaxial compressive strength and elastic modulus only decreased by 41.04%and 33.51%,respectively.Temperature has a significant effect on the expansion of volumetric strain,and the higher the temperature,the more obvious the volume expansion of the specimens.The cohesion and internal friction angle of granite after high temperature both decrease with temperature.(2)When the temperature is higher than 400℃,the changes in strength and deformation parameters of granite greatly increases,and the density and average width of microcracks also present a sudden-increase trend overall.Meanwhile,the failure mode of the specimens under uniaxial compression conditions changes from axial splitting failure to shear failure.The threshold temperature for the strength and deformation parameters and failure mode of granite is higher than 400℃.(3)The microcrack area(φs)and average microcrack width(Wa)both gradually increase with temperature.At 400℃,φs and Wa increase to 1.52%and 7.30 μm.As the temperature further rises to 600℃,φs and Wa reach 3.67%and 11.00 μm,respectively,corresponding to the decreasing trend of mechanical and deformation parameters with temperature.It is found that the escape of water molecules inside rock bodies,differences in mineral crystal expansion coefficients and mineral chemical changes lead to the initiation,propagation and interaction of microcracks among and within crystals in the granite,which ultimately induces the changes in the mechanical properties of the granite.The combination of macroscopic and microscopic experimental results reveals the physical and mechanical changes in reservoir granite under high-temperature and high-pressure conditions,which provides provide a theoretical basis for the design calculations and numerical simulations of high-temperature rock engineering projects.关键词
高温花岗岩/三轴压缩/力学特性/偏光显微镜/矿物晶体膨胀Key words
heat-treated granite/triaxial compression/mechanical properties/polarization microscope/mineral crystal expansion分类
建筑与水利引用本文复制引用
ZHU Zhennan,TIAN Hong,JIANG Guosheng,CHEN Jin,LIANG Yuan,XIE Jingyu,QIAO Wei,YANG Shengqi,YANG Xianyu,HUANG Yanhua,ZHANG Yu,FAN Hao..高温后花岗岩三轴压缩条件下力学特性试验研究[J].岩土工程学报,2026,48(1):33-44,12.基金项目
国家自然科学基金项目(42207178,42472334,42102353) （42207178,42472334,42102353）
江苏省国际科技合作计划-重点国别产业技术研发合作项目(BZ2024023) （BZ2024023）
岩土钻掘与防护教育部工程研究中心开放基金课题(202313) （202313）
江苏省自然科学基金青年项目(BK20231080) （BK20231080）
中国科协青年人才托举工程项目(2023QNRC001)This work was supported by National Natural Science Foundation of China(Grant No.42207178,42472334 and 42102353),Jiangsu Province International Collaboration Program-Key National Industrial Technology Research and Development Cooperation Project(Grant No.BZ2024023),Open Research Fund of Engineering Research Center of Rock-Soil Drilling&Excavation and Protection,Ministry of Education(Grant No.202313),Jiangsu Provincial Youth Fund Project(Grant No.BK20230125),and Youth Talent Support Program of the China Association for Science and Technology(Grant No.2023QNRC001). （2023QNRC001）
