• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
锦屏深部大理岩蠕变特性及分数阶蠕变模型
  • Title

    Creep characteristics and creep model of deep buried marble at Jinping underground laboratory

  • 作者

    许多吴世勇张茹张泽天周济芳邓建辉任利吴斐

  • Author

    XU Duo1 ,WU Shiyong2 ,ZHANG Ru1 ,ZHANG Zetian1 ,ZHOU Jifang2 ,DENG Jianhui1 ,REN Li3 ,WU Fei4

  • 单位

    四川大学 水利水电学院雅砻江流域水电开发有限公司四川大学 深地科学与工程教育部重点实验室重庆大学 煤矿灾害动力学与控制国家重点实验室

  • Organization
    1. College of Hydraulic and Hydroelectric Engineering,Sichuan University,Chengdu  610065,China; 2. Yalong River Hydropower Development Company, Ltd. ,Chengdu  610051,China;3 MOE Key Laboratory of Deep Earth Science and Engineering,Sichuan University,Chengdu  610065,China; 4. State Key Laboratory for the Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing  400044,China
  • 摘要

    为保障锦屏地下实验室(CJPL)硐室群的长期稳定性,开展2 400 m深埋大理岩蠕变特性的研究,在常规三轴压缩试验的基础上进行分级加载蠕变试验,系统分析了大理岩蠕变过程中的轴向与环向变形规律及不同围压(5 MPa和64 MPa)下大理岩蠕变特征差异,采用等时应力-应变曲线法确定了大理岩的长期强度,并基于分数阶导数改进了大理岩蠕变模型。研究表明:13,27 MPa围压下,大理岩轴向应力应变曲线达到峰值应力后快速跌落,40,53,64 MPa围压下,峰值应力附近的应变曲线呈现明显的平台段,表明CJPL深部大理岩变形行为随着围压的增加具有由脆性向延性转化的趋势;无论是低围压还是高围压,相比于低应力水平,高应力水平下大理岩更容易发生蠕变变形且环向蠕变现象更加显著,蠕变过程中的扩容现象也更加明显,试样破坏时64 MPa围压条件下的体积蠕变变形为5 MPa围压下的16.3倍;在蠕变加载过程中,大理岩变形模量均为先增加后减小。变形模量增加阶段,高围压下增加幅度较低围压小,64 MPa围压下试样变形模量增加的幅值为1.8 GPa,小于5 MPa围压下的3.6 GPa,表明试样受高围压作用已经部分压密。随着应力水平的增大,变形模量减小,高围压下减小幅度较低围压更大,围压64 MPa下试样变形模量减小幅值为9.4 GPa,约为峰值变形模量的22%,围压5 MPa下试样减小幅值仅为1.8 GPa,约为峰值变形模量的4%,表明高围压试样在破坏前裂纹的产生和扩展更为剧烈,岩石劣化程度更大;相同偏应力条件下,围压越大的试样蠕变速率越小,但破坏时变形更大且扩容现象显著,表明相同外荷载条件下,深部围岩赋存环境应力水平较高,变形难以收敛,易发生时效大变形破坏;围压为5,64 MPa时,采用等时应力-应变曲线法确定大理岩长期强度分别为170,290 MPa,为相应围压三轴压缩强度的82%,73%;基于分数阶导数,改进了大理岩黏弹塑性损伤蠕变模型,该模型具有形式简单同时能够很好的描述大理岩蠕变过程中的非线性加速特征的特点。

  • Abstract
    In order to ensure the long-term stability of Jinping Underground Laboratory ( CJPL) caverns,the creep characteristics of 2 400 m deep-buried marble were studied. The multi-stage loading creep tests were conducted on the basis of convention triaxial compression tests to analyze the law of axial and circumferential deformation of marble dur- ing the creep process and the difference of creep characteristics of marble under different confining pressures (5 and 64 MPa). Then the long-term strength of marble was discussed by using the isochronous stress-strain curve method and a creep model based on fractional derivative was proposed to describe the process of creep deformation. The results show that under the confining pressures of 13 MPa and 27 MPa,the axial stress-strain curves of marble drop rapidly af- ter reaching the peak stress and under confining pressures of 40,53 and 64 MPa,the strain curves near the peak stress show obvious plateau section,which indicates that the deformation behavior of deep marble in CJPL tends to change from brittleness to ductility with the increase of confining pressures. Compared with low stress level,the marble under high stress level is more prone to creep,the circumferential creep phenomenon is more significant and the dilatancy phenomenon during creep process is more obvious. The volume creep deformation of specimens under 64 MPa confi- ning pressure is 16. 3 times of that under 5 MPa confining pressure. During the creep loading process,the deformation modulus of marble increases first and then decreases. In the stage of increasing modulus of deformation,the increasing range under high confining pressure is smaller than that under low confining pressure. The increase of deformation modulus under 64 MPa confining pressure is 1. 8 GPa,less than 3. 6 GPa under 5 MPa confining pressure,which indi- cates that the specimen has been partially compacted under high confining pressure. With the increase of stress level, the modulus of deformation decreases and the decrease range under high confining pressure is greater than that under low confining pressure. The decrease of deformation modulus of specimens under confining pressure of 64 MPa is 9. 4 GPa,which is about 22% of the peak deformation modulus. The decrease of specimen under confining pressure of 5 MPa is only 1. 8 GPa,which is about 4% of the peak deformation modulus. These indicates that the crack initiation and propagation of specimens under high confining pressure are more intense and the rock deterioration is more serious before failure. Under the same deviating stress condition,the creep rate of specimens with larger confining pressure is smaller,but the deformation is larger and the dilatancy phenomenon is remarkable when the failure occurs. It shows that under the same external load condition,when the environmental stress level of deep surrounding rock is higher,the deformation of surrounding rock is difficult to converge,and it is prone to aging large deformation failure. When the confining pressure is 5 and 64 MPa,the long-term strength of marble is 170 and 290 MPa,respectively,which are 82% and 73% of the corresponding triaxial compressive strength. Based on the fractional derivative,a new viscous-e- lastic-plastic damage creep model of marble was established and it was proved that the model is simple in form and can well describe the characteristics of non-linear acceleration in marble creep process.
  • 关键词

    深部大理岩蠕变长期强度分数阶导数

  • KeyWords

    depth;marble;creep;long-term strength;fractional derivative

  • 基金项目(Foundation)
    国家重点研发计划资助项目(2016YFC0600702);国家优秀青年科学基金资助项目(51622402);四川省青年科技创新研究团队资助项目(2017TD0007)
  • DOI
  • Citation
    XU Duo,WU Shiyong,ZHANG Ru,et al. Creep characteristics and creep model of deep buried marble at Jinping un- derground laboratory[J]. Journal of China Coal Society,2019,44(5):1456-1464.
  • 相关文章
  • 相关专题
  • 图表
相关问题

主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会

©版权所有2015 煤炭科学研究总院有限公司 地址:北京市朝阳区和平里青年沟东路煤炭大厦 邮编:100013
京ICP备05086979号-16  技术支持:云智互联