川西北茂县群千枚岩各向异性力学特性
|
摘要
利用MTS815Teststar岩石力学试验系统,对川西北茂县群千枚岩开展单轴和三轴试验,研究千枚岩各向异性力学特性。研究结果表明:千枚岩在达到峰值强度50%以前就普遍出现很大的变形和局部破坏,表明围岩产生大变形或出现早期扩容并不意味着其丧失承载能力,如及时进行针对性支护或加强围岩保护仍具有较强的强度。损伤扩容是千枚岩变形破坏的典型特征,并对变形产生不同的影响,横向应变对损伤扩容比轴向应变更敏感,能更灵敏地反映岩石材料内部的屈服、弱化。千枚岩各向异性随含水率与围压水平表现出不同的变化规律,强度各向异性随含水率和围压水平提高而降低,弹性模量和泊松比则与加载方向和转化围压有关。不同含水状态下干燥千枚岩的单轴抗压强度各向异性最为显著,大部分千枚岩的强度各向异性率在0.80以下,其中绢云母千枚岩最强,为0.48,其强弱对比依次为绢云母千枚岩、绿泥石千枚岩、石英千枚岩、炭质千枚岩。千枚岩表现出不同的破坏模式,并随围压或含水率的增加而变化;剪切机制单独控制着各向异性力学特性,千枚岩统一沿软弱面剪切破坏。
This study aims to investigate the anisotropic characteristics of phyllite in Maoxian group from the northwest of Sichuan province in China. A series of uniaxial and triaxial compressive tests is conducted on phyllite samples by using the MTS815 Teststar rock mechanics testing system. Experimental results show that the large deformation and partial failure generally appear before samples reach half of their peak strengths. However, the occurrences of large deformation or initial dilatancy do not indicate that rock completely loses its bearing capacity. If the targeted support or protection can be applied on surrounding rock in time, rock strength is still strong. Damage dilation is regarded as a typical deformation and failure characteristic of phyllite. Furthermore, it affects lateral deformation more easily than axial deformation. Thus, lateral deformation can reflect rock yield or weakening more sensitively. Results show that the anisotropy of rock strength decreases with increasing water content and confining pressure. Moreover, Young's modulus and Poisson's ratio vary with the loading direction and translated-confining pressure. From the obtained results of phyllite at different water contents, the strength of phyllite under dry condition presents the most obvious anisotropic characteristics in uniaxial compressive tests. It is found that the anisotropic ratios of compressive strength are mainly below 0.8. Especially, sericite phyllite exhibits the strongest anisotropy with a ratio of 0.48, and the following anisotropic orders from strong to weak are sericite phyllite, chlorite phyllite, quartz phyllite, and carbonaceous phyllite. Moreover, there are different failure modes of phyllite, which also change with the increase of confining pressure and water content. Shear failure occurred uniformly along the weak planes, which indicates that the anisotropic mechanical characteristics of phyllite are controlled by shear mechanism independently.
This study aims to investigate the anisotropic characteristics of phyllite in Maoxian group from the northwest of Sichuan province in China. A series of uniaxial and triaxial compressive tests is conducted on phyllite samples by using the MTS815 Teststar rock mechanics testing system. Experimental results show that the large deformation and partial failure generally appear before samples reach half of their peak strengths. However, the occurrences of large deformation or initial dilatancy do not indicate that rock completely loses its bearing capacity. If the targeted support or protection can be applied on surrounding rock in time, rock strength is still strong. Damage dilation is regarded as a typical deformation and failure characteristic of phyllite. Furthermore, it affects lateral deformation more easily than axial deformation. Thus, lateral deformation can reflect rock yield or weakening more sensitively. Results show that the anisotropy of rock strength decreases with increasing water content and confining pressure. Moreover, Young's modulus and Poisson's ratio vary with the loading direction and translated-confining pressure. From the obtained results of phyllite at different water contents, the strength of phyllite under dry condition presents the most obvious anisotropic characteristics in uniaxial compressive tests. It is found that the anisotropic ratios of compressive strength are mainly below 0.8. Especially, sericite phyllite exhibits the strongest anisotropy with a ratio of 0.48, and the following anisotropic orders from strong to weak are sericite phyllite, chlorite phyllite, quartz phyllite, and carbonaceous phyllite. Moreover, there are different failure modes of phyllite, which also change with the increase of confining pressure and water content. Shear failure occurred uniformly along the weak planes, which indicates that the anisotropic mechanical characteristics of phyllite are controlled by shear mechanism independently.
引文
[1]杜宇本,袁传保,王彦东,等.成兰铁路主要地质灾害和地质选线[J].铁道工工程学报,2012,8(216):11-15.DU Yu-beng,YUAN Chuan-bao,WANG Yan-dong,et al.Major geological hazard and geological alignment of Chengdu-Lanzhou railway[J].Journal of Railway Engineering Society,2012,8(216):11-15.
[2]王思敬.论岩石的地质本质性及其岩石力学演绎[J].岩石力学与工程学报,2009,28(3):433-450.WANG Si-jing.Geotechnical nature of rock and its deduction for rock mechanics[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(3):433-450.
[3]RAMAMURTHY T.千枚岩的工程性能[J].国外科技,1994,25(12):48-52.RAMAMURTHY T.Engineering properties of phyllite[J].Foreign Science and Technology,1994,25(12):48-52.
[4]郑达,巨能攀.千枚岩岩石微观破裂机理与断裂特征研究[J].工程地质学报,2011,19(3):317-322.ZHENG Da,JU Neng-pan.Study on micro-rupture mechanism and fracture characteristic of phyllite[J].Journal of Engineering Geology,2011,19(3):317-322.
[5]刘云鹏,邓辉,黄润秋.板裂结构岩石力学试验及破裂断口细观形貌特征分析[J].岩石力学与工程学报,2005,34(增刊2):3854-3860.LIU Yun-peng,DENG Hui,HUANG Run-qiu.Mechanical test of slad-rent structure rock and mesoscopic morphology analysis of rupture surface[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Supp.2):3854-3860.
[6]刘胜利,陈善雄,余飞,等.绿泥石片岩各向异性特性研究[J].岩土力学,2012,33(12):3616-3623.LIU Sheng-li,CHEN Shan-xiong,YU Fei,et al.Anisotropic properties study of chlorite schist[J].Rock and Soil Mechanics,2012,33(12):3616-3623.
[7]王章琼,晏鄂川,黄祥嘉,等.鄂西北片岩变形参数各向异性及水敏性研究[J].岩石力学与工程学报,2014,33(增刊2):3967-3973.WANG Zhang-qiong,YAN E-chuan,HUANG Xiang-jia,et al.Anisotropic and water sensitivity properties study of schist deformation parameters in northwest of Hubei province[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Supp.2):3967-3973.
[8]何满潮,景海河,孙晓明.软岩工程力学[M].北京:科学出版社,2002.HE Man-chao,JING Hai-he,SUN Xiao-ming.Mechanics for soft rocks[M].Beijing:Science Press,2002.
[9]张晓平,王思敬,韩庚友,等.岩石单轴压缩条件下裂纹扩展试验研究——以片状岩石为例[J].岩石力学与工程学报,2003,22(6):894-898.ZHANG Xiao-ping,WANG Si-jing,HAN Geng-you,et al.Crack propagation study of rock based on uniaxial compressive test—a case study of schistose rock[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(6):894-898.
[10]POUYA A,GHOREYCHI M.Determination of rock mass strength properties by homogenization[J].International Journal for Numerical and Analytical Methods in Geomechanics,2001,25(13):1285-1303.
[11]徐志英.岩石力学[M].北京:中国水利水电出版社,2002.XU Zhi-ying.Rock mechanics[M].Beijing:Water Conservancy and Electricity Publication of China,2002.
[12]王林,龙冈文夫.关于沉积软岩固有各向异性特性的研究[J].岩石力学与工程学报,2011,30(9):1772-1781.WANG Lin,TATSUOKA Fumio.Examining anisotropy of sedimentary soft rock[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(9):1772-1781.
[13]郭富利,张顶立,苏洁,等.地下水和围压对软岩力学性质影响的试验研究[J].岩石力学与工程学报,2007,26(11):2324-2332.GUO Fu-li,ZHANG Ding-li,SU Jie,et al.Experimental study on influences of groundwater and confining pressure on mechanical behaviors of soft rocks[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(11):2324-2332.
[14]高春玉,徐进,李忠洪,等.雪峰山隧道砂板岩各向异性力学特性的试验研究[J].岩土力学,2011,32(5):1360-1364.GAO Chun-yu,XU Jin,LI Zhong-hong,et al.Experimental study of anisotropically mechanical characteristics of sandy slate in Xuefeng mountain tunnel[J].Rock and Soil Mechanics,2011,32(5):1360-1364.
[15]张贵科,徐卫亚.节理岩体正交各向异性等效强度参数研究[J].岩土工程学报,2007,32(6):908-915.ZHANG Gui-ke,XU Wei-ya.Orthotropic equivalent deformation parameters of jointed rock mass[J].Chinese Journal of Geotechnical Engineering,2007,32(6):908-915.
[16]刘高.高应力区结构性流变围岩稳定性研究[D].成都:成都理工大学,2001.LIU Gao.Stability study of surrounding rock with structural rheology in high stress area[D].Chengdu:Chengdu University of Technology,2001.
[17]吴永胜,谭忠盛,李少孟.挤压性大变形隧道围岩基本特性的试验研究[J].土木工程学报,2015,48(1):398-402.WU Yong-sheng,TAN Zhong-sheng LI Shao-meng.Experimental study on the basic characteristics of tunnel in squeezing surrounding rock with large deformation[J]China Civil Engineering Journal,2015,48(1):398-402.
[2]王思敬.论岩石的地质本质性及其岩石力学演绎[J].岩石力学与工程学报,2009,28(3):433-450.WANG Si-jing.Geotechnical nature of rock and its deduction for rock mechanics[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(3):433-450.
[3]RAMAMURTHY T.千枚岩的工程性能[J].国外科技,1994,25(12):48-52.RAMAMURTHY T.Engineering properties of phyllite[J].Foreign Science and Technology,1994,25(12):48-52.
[4]郑达,巨能攀.千枚岩岩石微观破裂机理与断裂特征研究[J].工程地质学报,2011,19(3):317-322.ZHENG Da,JU Neng-pan.Study on micro-rupture mechanism and fracture characteristic of phyllite[J].Journal of Engineering Geology,2011,19(3):317-322.
[5]刘云鹏,邓辉,黄润秋.板裂结构岩石力学试验及破裂断口细观形貌特征分析[J].岩石力学与工程学报,2005,34(增刊2):3854-3860.LIU Yun-peng,DENG Hui,HUANG Run-qiu.Mechanical test of slad-rent structure rock and mesoscopic morphology analysis of rupture surface[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Supp.2):3854-3860.
[6]刘胜利,陈善雄,余飞,等.绿泥石片岩各向异性特性研究[J].岩土力学,2012,33(12):3616-3623.LIU Sheng-li,CHEN Shan-xiong,YU Fei,et al.Anisotropic properties study of chlorite schist[J].Rock and Soil Mechanics,2012,33(12):3616-3623.
[7]王章琼,晏鄂川,黄祥嘉,等.鄂西北片岩变形参数各向异性及水敏性研究[J].岩石力学与工程学报,2014,33(增刊2):3967-3973.WANG Zhang-qiong,YAN E-chuan,HUANG Xiang-jia,et al.Anisotropic and water sensitivity properties study of schist deformation parameters in northwest of Hubei province[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Supp.2):3967-3973.
[8]何满潮,景海河,孙晓明.软岩工程力学[M].北京:科学出版社,2002.HE Man-chao,JING Hai-he,SUN Xiao-ming.Mechanics for soft rocks[M].Beijing:Science Press,2002.
[9]张晓平,王思敬,韩庚友,等.岩石单轴压缩条件下裂纹扩展试验研究——以片状岩石为例[J].岩石力学与工程学报,2003,22(6):894-898.ZHANG Xiao-ping,WANG Si-jing,HAN Geng-you,et al.Crack propagation study of rock based on uniaxial compressive test—a case study of schistose rock[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(6):894-898.
[10]POUYA A,GHOREYCHI M.Determination of rock mass strength properties by homogenization[J].International Journal for Numerical and Analytical Methods in Geomechanics,2001,25(13):1285-1303.
[11]徐志英.岩石力学[M].北京:中国水利水电出版社,2002.XU Zhi-ying.Rock mechanics[M].Beijing:Water Conservancy and Electricity Publication of China,2002.
[12]王林,龙冈文夫.关于沉积软岩固有各向异性特性的研究[J].岩石力学与工程学报,2011,30(9):1772-1781.WANG Lin,TATSUOKA Fumio.Examining anisotropy of sedimentary soft rock[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(9):1772-1781.
[13]郭富利,张顶立,苏洁,等.地下水和围压对软岩力学性质影响的试验研究[J].岩石力学与工程学报,2007,26(11):2324-2332.GUO Fu-li,ZHANG Ding-li,SU Jie,et al.Experimental study on influences of groundwater and confining pressure on mechanical behaviors of soft rocks[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(11):2324-2332.
[14]高春玉,徐进,李忠洪,等.雪峰山隧道砂板岩各向异性力学特性的试验研究[J].岩土力学,2011,32(5):1360-1364.GAO Chun-yu,XU Jin,LI Zhong-hong,et al.Experimental study of anisotropically mechanical characteristics of sandy slate in Xuefeng mountain tunnel[J].Rock and Soil Mechanics,2011,32(5):1360-1364.
[15]张贵科,徐卫亚.节理岩体正交各向异性等效强度参数研究[J].岩土工程学报,2007,32(6):908-915.ZHANG Gui-ke,XU Wei-ya.Orthotropic equivalent deformation parameters of jointed rock mass[J].Chinese Journal of Geotechnical Engineering,2007,32(6):908-915.
[16]刘高.高应力区结构性流变围岩稳定性研究[D].成都:成都理工大学,2001.LIU Gao.Stability study of surrounding rock with structural rheology in high stress area[D].Chengdu:Chengdu University of Technology,2001.
[17]吴永胜,谭忠盛,李少孟.挤压性大变形隧道围岩基本特性的试验研究[J].土木工程学报,2015,48(1):398-402.WU Yong-sheng,TAN Zhong-sheng LI Shao-meng.Experimental study on the basic characteristics of tunnel in squeezing surrounding rock with large deformation[J]China Civil Engineering Journal,2015,48(1):398-402.