锦屏深部大理岩蠕变特性及分数阶蠕变模型
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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。
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 during the creep process and the difference of creep characteristics of marble under different confining pressures(5 and64 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 after 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 confining 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 indicates 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 is9. 4 GPa,which is about 22% of the peak deformation modulus. The decrease of specimen under confining pressure of5 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 are82% and 73% of the corresponding triaxial compressive strength. Based on the fractional derivative,a new viscous-elastic-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.
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 during the creep process and the difference of creep characteristics of marble under different confining pressures(5 and64 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 after 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 confining 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 indicates 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 is9. 4 GPa,which is about 22% of the peak deformation modulus. The decrease of specimen under confining pressure of5 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 are82% and 73% of the corresponding triaxial compressive strength. Based on the fractional derivative,a new viscous-elastic-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.
引文
[1]谢和平,高峰,鞠杨,等.深地科学领域的若干颠覆性技术构想和研究方向[J].工程科学与技术,2017,49(1):1-8.XIE Heping,GAO Feng,JU Yang,et al.Novel ideal and disruptive technologies for the exploration and research of deep earth[J].Advanced Engineering Sciences,2017,49(1):1-8.
[2]谢和平,高明忠,张茹,等.地下生态城市与深地生态圈战略构想及其关键技术展望[J].岩石力学与工程学报,2017,36(6):1301-1313.XIE Heping,GAO Mingzhong,ZHANG Ru,et al.The subversive idea and its key technical prospect on underground ecological city and ecosytem[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(6):1301-1313.
[3]张春生,陈详荣,侯靖,等.锦屏二级水电站深埋大理岩力学特性研究[J].岩石力学与工程学报,2010,29(10):1999-2009.ZHANG Chunsheng,CHEN Xiangrong,HOU Jing,et al.Study of mechanical behavior of deep-buried marble at Jinping II hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):1999-2009.
[4]王来贵,赵娜,何峰,等.岩石蠕变损伤模型极其稳定性分析[J].煤炭学报,2009,34(1):64-68.WANG Laigui,ZHAO Na,HE Feng,et al.Rock creep damage model and its stability analysis[J].Journal of China Coal Society,2009,34(1):64-68.
[5]孙钧.岩石流变力学及其工程应用研究的若干进展[J].岩石力学与工程学报,2007,26(6):1081-1106.SUN Jun.Rock rheological mechanics and its advance in engineering applications[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(6):1081-1106.
[6]杨圣奇,徐卫亚,谢守益,等.饱和状态下硬岩三轴流变变形与破裂机制研究[J].岩土工程学报,2006,28(8):962-969.YANG Shengqi,XU Weiya,XIE Shouyi,et al.Studies on triaxial rheological deformation and failure mechanismof hard rock in saturated state[J].Chinese Journal of Geotechnical Engineering,2006,28(8):962-969.
[7]王芝银,艾传志,唐明明.不同应力下岩石蠕变全过程[J].煤炭学报,2009,34(2):169-174.WANG Zhiyin,AI Chuanzhi,TANG Mingming.Complete process of rock creep in different stress states[J].Journal of China Coal Society,2009,34(2):169-174.
[8]张龙云,张强勇,李术才,等.硬脆性岩石卸荷流变试验及长期强度研究[J].煤炭学报,2015,40(10):2399-2407.ZHANG Longyun,ZHANG Qiangyong,LI Shucai,et al.Unloading rheological tests of hard brittle rock and its long-term strength analysis[J].Journal of China Coal Society,2015,40(10):2399-2407.
[9]陈亮,刘建峰,王春萍,等.不同温度及应力状态下北山花岗岩蠕变特征研究[J].岩石力学与工程学报,2015,34(6):1228-1235.CHEN Liang,LIU Jianfeng,WANG Chunping,et al.Creeping behavior of Beishan granite under different temperatures and stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(6):1228-1235.
[10]徐子杰,齐庆新,李宏艳,等.不同应力水平下大理岩蠕变损伤声发射特性[J].煤炭学报,2014,39(S1):70-74.XU Zijie,QI Qingxin,LI Hongyan,et al.Marble creep damage and acoustic emission characteristics under different stress levels[J].Journal of China Coal Society,2014,39(S1):70-74.
[11]闫子舰,夏才初,李宏哲,等.分级卸荷条件下锦屏大理岩流变规律研究[J].岩石力学与工程学报,2008,27(10):2153-2159.YAN Zijian,XIE Caichu,LI Hongzhe,et al.Study on rheological rules of marble in Jinping hydropower station under condition of step unloading[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(10):2153-2159.
[12]陈文,孙洪广,李西成.力学与工程问题的分数阶导数建模[M].北京:科学出版社,2010.
[13]陈军浩,姚兆明,徐颖,等.人工冻土蠕变特性粒子群分数阶导数模型[J].煤炭学报,2013,38(10):1763-1768.CHEN Junhao,YAO Zhaoming,XU Ying,et al.Particel swarm fractional order derivative model of artificial frozen soil creep properties[J].Journal of China Coal Society,2013,38(10):1763-1768.
[14]周宏伟,王春萍,段志强,等.基于分数阶导数的盐岩流变本构模型[J].中国科学:物理学力学天文学,2012(3):310-318.ZHOU Hongwei,WANG Chunping,DUAN Zhiqiang,et al.The rheological constitutive model of salt rock based on fractional derivative[J].Scientia Sinica Physica,Mechanica&Astronomica,2012(3):310-318.
[15]吴斐,谢和平,刘建锋,等.分数阶黏弹塑性蠕变模型试验研究[J].岩石力学与工程学报,2014,33(5):964-970.WU Fei,XIE Heping,LIU Jianfeng,et al.Experimental study of fractional viscoelastic-plastic creep madel[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(5):964-970.
[16]汪斌,朱杰兵,邬爱清,等.锦屏大理岩加、卸载应力路径下力学性质试验研究[J].岩石力学与工程学报,2008,27(10):2138-2145.WANG Bin,ZHU Jiebing,WU Aiqing,et al.Experimental study on mechanical properties of Jinping marble under loading and unloading stress paths[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(10):2138-2145.
[17]MARTIN C D,CHANDLER N A.The progressive fracture of Lac du Bonnet granite[A].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts[C].Pergamon,1994,31(6):643-659.
[18]张强勇,杨文东,陈芳,等.硬脆性岩石的流变长期强度及细观破裂机制分析研究[J].岩土工程学报,2011,33(12):1910-1918.ZHANG Qiangyong,YANG Wendong,CHEN Fang,et al.Long-term strength and microscopic failure mechanism of hard brittle rocks[J].Chinese Journal of Geotechnical Engineering,2011,33(12):1910-1918.
[19]沈明荣,谌洪菊.红砂岩长期强度特性的试验研究[J].岩土力学,2011,32(11):3301-3305.SHEN Mingrong,CHEN Hongju.Testing study of long-term strength characteristics of red sandstone[J].Rock and Soil Mechanics,2011,32(11):3301-3305.
[20]杨逾,李盈,周小科.基于西原加速模型的煤岩蠕变试验研究[J].煤炭学报,2014,36(11):2190-2194.YANG Yu,LI Ying,ZHOU Xiaoke.Study on the coal creep test based on the improved Nishihara model[J].Journal of China Coal Society,2014,36(11):2190-2194.
[2]谢和平,高明忠,张茹,等.地下生态城市与深地生态圈战略构想及其关键技术展望[J].岩石力学与工程学报,2017,36(6):1301-1313.XIE Heping,GAO Mingzhong,ZHANG Ru,et al.The subversive idea and its key technical prospect on underground ecological city and ecosytem[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(6):1301-1313.
[3]张春生,陈详荣,侯靖,等.锦屏二级水电站深埋大理岩力学特性研究[J].岩石力学与工程学报,2010,29(10):1999-2009.ZHANG Chunsheng,CHEN Xiangrong,HOU Jing,et al.Study of mechanical behavior of deep-buried marble at Jinping II hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):1999-2009.
[4]王来贵,赵娜,何峰,等.岩石蠕变损伤模型极其稳定性分析[J].煤炭学报,2009,34(1):64-68.WANG Laigui,ZHAO Na,HE Feng,et al.Rock creep damage model and its stability analysis[J].Journal of China Coal Society,2009,34(1):64-68.
[5]孙钧.岩石流变力学及其工程应用研究的若干进展[J].岩石力学与工程学报,2007,26(6):1081-1106.SUN Jun.Rock rheological mechanics and its advance in engineering applications[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(6):1081-1106.
[6]杨圣奇,徐卫亚,谢守益,等.饱和状态下硬岩三轴流变变形与破裂机制研究[J].岩土工程学报,2006,28(8):962-969.YANG Shengqi,XU Weiya,XIE Shouyi,et al.Studies on triaxial rheological deformation and failure mechanismof hard rock in saturated state[J].Chinese Journal of Geotechnical Engineering,2006,28(8):962-969.
[7]王芝银,艾传志,唐明明.不同应力下岩石蠕变全过程[J].煤炭学报,2009,34(2):169-174.WANG Zhiyin,AI Chuanzhi,TANG Mingming.Complete process of rock creep in different stress states[J].Journal of China Coal Society,2009,34(2):169-174.
[8]张龙云,张强勇,李术才,等.硬脆性岩石卸荷流变试验及长期强度研究[J].煤炭学报,2015,40(10):2399-2407.ZHANG Longyun,ZHANG Qiangyong,LI Shucai,et al.Unloading rheological tests of hard brittle rock and its long-term strength analysis[J].Journal of China Coal Society,2015,40(10):2399-2407.
[9]陈亮,刘建峰,王春萍,等.不同温度及应力状态下北山花岗岩蠕变特征研究[J].岩石力学与工程学报,2015,34(6):1228-1235.CHEN Liang,LIU Jianfeng,WANG Chunping,et al.Creeping behavior of Beishan granite under different temperatures and stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(6):1228-1235.
[10]徐子杰,齐庆新,李宏艳,等.不同应力水平下大理岩蠕变损伤声发射特性[J].煤炭学报,2014,39(S1):70-74.XU Zijie,QI Qingxin,LI Hongyan,et al.Marble creep damage and acoustic emission characteristics under different stress levels[J].Journal of China Coal Society,2014,39(S1):70-74.
[11]闫子舰,夏才初,李宏哲,等.分级卸荷条件下锦屏大理岩流变规律研究[J].岩石力学与工程学报,2008,27(10):2153-2159.YAN Zijian,XIE Caichu,LI Hongzhe,et al.Study on rheological rules of marble in Jinping hydropower station under condition of step unloading[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(10):2153-2159.
[12]陈文,孙洪广,李西成.力学与工程问题的分数阶导数建模[M].北京:科学出版社,2010.
[13]陈军浩,姚兆明,徐颖,等.人工冻土蠕变特性粒子群分数阶导数模型[J].煤炭学报,2013,38(10):1763-1768.CHEN Junhao,YAO Zhaoming,XU Ying,et al.Particel swarm fractional order derivative model of artificial frozen soil creep properties[J].Journal of China Coal Society,2013,38(10):1763-1768.
[14]周宏伟,王春萍,段志强,等.基于分数阶导数的盐岩流变本构模型[J].中国科学:物理学力学天文学,2012(3):310-318.ZHOU Hongwei,WANG Chunping,DUAN Zhiqiang,et al.The rheological constitutive model of salt rock based on fractional derivative[J].Scientia Sinica Physica,Mechanica&Astronomica,2012(3):310-318.
[15]吴斐,谢和平,刘建锋,等.分数阶黏弹塑性蠕变模型试验研究[J].岩石力学与工程学报,2014,33(5):964-970.WU Fei,XIE Heping,LIU Jianfeng,et al.Experimental study of fractional viscoelastic-plastic creep madel[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(5):964-970.
[16]汪斌,朱杰兵,邬爱清,等.锦屏大理岩加、卸载应力路径下力学性质试验研究[J].岩石力学与工程学报,2008,27(10):2138-2145.WANG Bin,ZHU Jiebing,WU Aiqing,et al.Experimental study on mechanical properties of Jinping marble under loading and unloading stress paths[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(10):2138-2145.
[17]MARTIN C D,CHANDLER N A.The progressive fracture of Lac du Bonnet granite[A].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts[C].Pergamon,1994,31(6):643-659.
[18]张强勇,杨文东,陈芳,等.硬脆性岩石的流变长期强度及细观破裂机制分析研究[J].岩土工程学报,2011,33(12):1910-1918.ZHANG Qiangyong,YANG Wendong,CHEN Fang,et al.Long-term strength and microscopic failure mechanism of hard brittle rocks[J].Chinese Journal of Geotechnical Engineering,2011,33(12):1910-1918.
[19]沈明荣,谌洪菊.红砂岩长期强度特性的试验研究[J].岩土力学,2011,32(11):3301-3305.SHEN Mingrong,CHEN Hongju.Testing study of long-term strength characteristics of red sandstone[J].Rock and Soil Mechanics,2011,32(11):3301-3305.
[20]杨逾,李盈,周小科.基于西原加速模型的煤岩蠕变试验研究[J].煤炭学报,2014,36(11):2190-2194.YANG Yu,LI Ying,ZHOU Xiaoke.Study on the coal creep test based on the improved Nishihara model[J].Journal of China Coal Society,2014,36(11):2190-2194.
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