| 高温作用后花岗岩三轴压缩试验研究 |
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| 引用本文： | 徐小丽,高峰,张志镇.高温作用后花岗岩三轴压缩试验研究[J].岩土力学,2014,35(11):3177-3183. |
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| 作者姓名： | 徐小丽 高峰 张志镇 |
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| 作者单位： | 1.南通大学 建筑工程学院，江苏 南通 226019；2.中国矿业大学 深部岩土力学与地下工程国家重点实验室，江苏 徐州 221008 |
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| 基金项目： | 国家自然科学基金(No. 11202108）；中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金(No. SKLGDUEK1204）；南通大学前期预研科研项目(No. 11ZY006）。 |
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| 摘 要： | 为综合考察温度、围压对花岗岩力学性质及破坏方式的影响,在高温(25℃1 000℃)作用后,利用MTS815.02电液伺服材料试验系统对花岗岩岩样进行不同围压作用下的三轴压缩试验。研究结果表明,(1)围压一定时,经历不同高温作用后花岗岩三轴压缩全应力-应变曲线经历了压密、弹性、屈服、破坏、塑性流动5个阶段;(2)经历不同高温作用后岩样三轴抗压强度与围压呈非线性二次多项式增长关系,围压为40 MPa时的抗压强度比单轴抗压强度提高了382.30%;常规三轴压缩条件下,400℃是花岗岩力学参数的阀值温度;(3)经历高温作用后,岩样弹性模量随围压升高呈增大趋势,围压为40 MPa时的弹性模量比单轴时提高了90.26%;随温度升高呈二次非线性减小,1 000℃时的弹性模量比25℃时降低了57.16%;(4)花岗岩的失稳型式同时取决于围压和温度。单轴压缩状态下,随着温度的升高,岩样变形破坏型式由脆性破裂向塑性变形过渡,失稳型式在低温时为突发失稳、中高温为准突发失稳,温度高于800℃为渐进破坏;三轴压缩状态下,随着围压的增大,岩样破裂型式由脆性张拉破裂逐渐向剪切破裂过渡,岩样的失稳型式以突发失稳为主。在试验温压范围内,影响花岗岩力学性质的首要因素是温度,其次是围压。
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| 关 键 词： | 花岗岩 温度 围压 力学性质 失稳型式 |
| 收稿时间： | 2013-07-14 |
Research on triaxial compression test of granite after high temperatures |
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| XU Xiao-li,GAO Feng,ZHANG Zhi-zhen.Research on triaxial compression test of granite after high temperatures[J].Rock and Soil Mechanics,2014,35(11):3177-3183. |
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| Authors: | XU Xiao-li GAO Feng ZHANG Zhi-zhen |
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| Institution: | 1. School of Architecture and Civil Engineering, Nantong University, Nantong, Jiangsu 226019, China; 2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China |
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| Abstract: | In order to study the effect of temperature and confining pressure on rock mechanical properties and failure mode, experiments on granite under triaxial compression of different confining pressure from 0 to 40 MPa were conducted after high temperature of 25-1 000 ℃ by the MTS815.02 servo-controlled testing machine. The results show that: (1) Complete stress-strain curves of granite which heated to various temperatures under conventional triaxial compression with fixed confining pressure have experienced compaction, elasticity, yield, failure and plastic flow five stages. (2) Relationship between triaxial compressive strength of granite and confining pressure after high temperatures is nonlinear quadratic polynomial relations. When the confining pressure is 40 MPa, the triaxial compressive strength is increased 382.30% than uniaxial compressive strength; 400 ℃ is the threshold temperature of granite mechanical parameters under conventional triaxial compression conditions. (3) Elastic modulus of granite tends to increase with the confining pressure and quadratic nonlinearly decrease with the temperature, which is increased 90.26% than that at uniaxial compression when the confining pressure is 40 MPa, and when the temperature is 1 000 ℃, it is decreased 57.16% than that at 25 ℃. (4) Form of deformation and failure of rock samples is from brittle fracture transiting to plastic deformation as the temperature increases under uniaxial compression state. Instability mode is sudden instability at low temperatures, quasi- abrupt instability at medium-high temperature, and progressive failure at temperature higher than 800 ℃. Rupture type of rock samples changes from brittle tensile fracture to shear fracture gradually with the increase of confining pressure under triaxial compression. Instability mode of rock is dominated by sudden instability. In the experimental temperature and pressure range, temperature is the primary factor affecting mechanical properties of rock samples, followed by confining pressure, while the instability mode of granite depends on both confining pressure and temperature. |
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| Keywords: | granite temperature confining pressure mechanical characteristics instability mode |
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