三轴试验下结构面倾角对制备岩样力学特性的影响
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摘要
结构面倾角对岩样的力学特性有很大影响。人工制备了结构面倾角为15°、30°、45°、60°(水平面为0°面)的单贯通结构面岩样和完整样,并进行了单轴压缩试验和围压为100、200、300 kPa的三轴压缩试验来探讨结构面倾角对其力学和变形特性的影响。试验结果表明:①当倾角小于等于30°时,出现了岩样应力-应变曲线中典型的4个阶段。而当倾角等于45°和60°时,最后阶段变为先软化再硬化的特征;②结构面岩样均先体缩再体胀。随着围压增加,体缩最大值接近,而体胀呈明显减小趋势。随结构面倾角增加,体缩呈缓慢增长趋势,并在30°和45°时出现体缩突变。而体胀显著的减小。最后,指出了耶格尔单结构面判据的不足,并对其进行了修正,验证结果表明改进的耶格尔判据与试验结果吻合较好。
The dip angle of structural plane has great influences on mechanical properties of rock samples. In this study, the rock samples with structural planes of 15°, 30°, 45°, 60°(the structural plane of 0° is along the horizontal direction)and the intact rock samples are prepared. Uniaxial tests and triaxial tests with confining pressures of 100 kPa, 200 kPa and 300 kPa are performed to investigate the influence of dip angle of structural planes on their mechanical and deformation features. Test results demonstrate that:1) the stress-strain curve exhibits the four typical stages, which are similar to those of rock samples when the dip angle is no more than 30°, but the last phase exhibits the characteristics of softening followed by hardening when the dip angle is equal to 45°or 60°,2) for all the samples, the contractive volumetric strain is firstly shown, and then the dilative volumetric strain is followed. With the increasing confining pressure, the maximum value of contractive volumetric strain does not change much, but the dilative volumetric strain obviously decreases. With the increase of the dip angle, the contractive volumetric strain slowly increases, and the contractive volumetric strain suddenly changes when the dip angle increases from 30° to 45°. However, the dilative volumetric strain obviously decreases. Finally, the disadvantage of Jaeger's single structural plane criterion is pointed out, and thus the criterion has been improved. The verification results denote that the improved Jaeger criterion is in good agreement with the experimental results.
The dip angle of structural plane has great influences on mechanical properties of rock samples. In this study, the rock samples with structural planes of 15°, 30°, 45°, 60°(the structural plane of 0° is along the horizontal direction)and the intact rock samples are prepared. Uniaxial tests and triaxial tests with confining pressures of 100 kPa, 200 kPa and 300 kPa are performed to investigate the influence of dip angle of structural planes on their mechanical and deformation features. Test results demonstrate that:1) the stress-strain curve exhibits the four typical stages, which are similar to those of rock samples when the dip angle is no more than 30°, but the last phase exhibits the characteristics of softening followed by hardening when the dip angle is equal to 45°or 60°,2) for all the samples, the contractive volumetric strain is firstly shown, and then the dilative volumetric strain is followed. With the increasing confining pressure, the maximum value of contractive volumetric strain does not change much, but the dilative volumetric strain obviously decreases. With the increase of the dip angle, the contractive volumetric strain slowly increases, and the contractive volumetric strain suddenly changes when the dip angle increases from 30° to 45°. However, the dilative volumetric strain obviously decreases. Finally, the disadvantage of Jaeger's single structural plane criterion is pointed out, and thus the criterion has been improved. The verification results denote that the improved Jaeger criterion is in good agreement with the experimental results.
引文
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[9]REIK G,ZACAS M.Strength and deformation characteristics of jointed media in true triaxial compression[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1978,15(6):295-303.
[10]杨圣奇,陆家炜,田文岭,等.不同节理粗糙度类岩石材料三轴压缩力学特性试验研究[J].岩土力学,2018,39(增刊1):21-32.YANG Sheng-qi,LU Jia-wei,TIAN Wen-ling,et al.Experimental study of mechanical behavior of rock specimens with different joint roughness coefficient under conventional triaxial compression[J].Rock and Soil Mechanics,2018,(Suppl.1):21-32.
[11]NASSERI M H,RAO K S,RAMAMURTHY T.Failure mechanism in schistose rocks[J].International Journal of Rock Mechanics&Mining Sciences,1997,34(3-4):460-460.
[12]ARZúA J,ALEJANO L R,WALTON G.Strength and dilation of jointed granite specimens in servo-controlled triaxial tests[J].International Journal of Rock Mechanics&Mining Sciences,2014,69(3):93-104.
[13]MEDHURST T P,BROWN E T.A study of the mechanical behaviour of coal for pillar design[J].International Journal of Rock Mechanics&Mining Sciences,1998,35(8):1087-1105.
[14]LIU M,LIU E.Dynamic mechanical properties of artificial jointed rock samples subjected to cyclic triaxial loading[J].International Journal of Rock Mechanics&Mining Sciences,2017,98(1):54-66.
[15]南京水利科学研究院.SL327-1999土工试验规程[S].北京:中国水利水电出版社,1999.Nanjing Hydraulic Research Institute.SL327-1999Rules of Geotechnical Testing[S].Beijing:China Water&Power Press,1999.
[16]CHO J W,KIM H,JEON S,et al.Deformation and strength anisotropy of Asan gneiss,Boryeong shale,and Yeoncheon schist[J].International Journal of Rock Mechanics&Mining Sciences,2012,50(2):158-169.
[17]XIAO W,DENG R,ZHONG Z,et al.Experimental study on the mechanical properties of simulated columnar jointed rock masses[J].Journal of Geophysics&Engineering,2015,12(1):80-89.
[18]耶格尔J C,库克N G W.岩石力学基础[M].中国科学院工程力学研究所译.北京:科学出版社,1981.JAEGER J C,COOK N G W.Fundamentals of rock mechanics[M].Translated by Institute of Mechanics,Chinese Academy of Sciences.Beijing:Science Press,1981.
[19]DONATH F A.Experimental study of shear failure in anisotropic rocks[J].Geological Society of America Bulletin,1961,72(6):985-989.
[20]SINGH M,RAO K S,RAMAMURTHY T.Strength and deformational behaviour of a jointed rock mass[J].Rock Mechanics&Rock Engineering,2002,35(1):45-64.
[21]张永兴,许明.岩石力学[M].北京:中国建筑工业出版社,2015.ZHANG Yong-xing,XU Ming.Rock mechanics[M].Beijing:China Architecture&Building Press,2015
[22]孙广忠.岩体力学原理[M].北京:科学出版社,2011.SUN Guang-zhong.Principle of rock mass mechanics[M].Beijing:Science Press,2011.
[23]HOEK E,BROWN E T,The Hoek-Brown failure criterion and GSI[J/OL].Journal of Rock Mechanics and Geotechnical Engineering,[2018-07-01].https://doi.org/10.1016/j.jrmge.2018.08.001.
[24]HOEK E.Strength of jointed rock masses[J].Géotechnique,1983,33(33):187-223.
[25]JAEGER J C,COOK N G W.Fundamentals of rock mechanics[M].London:Chapman and Hall,1969.
[26]韩建新,李术才,李树忱,等.贯穿裂隙岩体强度和破坏方式的模型研究[J].岩土力学,2011,32(增刊2):178-184.HAN Jian-xin,LI Shu-cai,LI Shu-chen,et al.Model study of strength and failure modes of rock mass with persistent cracks[J].Rock and Soil Mechanics,2011,32(Suppl.2):178-184.
[2]孙广忠.岩体结构力学[M].北京:科学出版社,1988.SUN Guang-zhong.Structural mechanics of rock[M].Beijing:Science Press,1988.
[3]RAMAMURTHY T,ARORA V K.Strength predictions for jointed rocks in confined and unconfined states[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1994,31(1):9-22.
[4]冒海军,杨春和.结构面对板岩力学特性影响研究[J].岩石力学与工程学报,2005,24(20):3651-3656.MAO Hai-jun,YANG Chun-he.Study on effects of discontinuities on mechanical characters of slate[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(20):3651-3656.
[5]WALSH J B,BRACE W F.A fracture criterion for brittle anisotropic rock[J].Journal of Geophysical Research,1964,69(16):3449-3456.
[6]李宏哲,夏才初,王晓东,等.含节理大理岩变形和强度特性的试验研究[J].岩石力学与工程学报,2008,27(10):2118-2123.LI Hong-zhe,XIA Cai-chu,WANG Xiao-dong,et al.Experimental study on deformation and strength properties of jointed marble specimens[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(10):2118-2123.
[7]向天兵,冯夏庭,陈炳瑞,等.三向应力状态下单结构面岩石试样破坏机制与真三轴试验研究[J].岩土力学,2009,30(10):2908-2916.XIANG Tian-bing,FENG Xia-ting,CHEN Bing-rui,et al.Rock failure mechanism and true triaxial experimental study of specimens with single structural plane under three-dimensional stress[J].Rock and Soil Mechanics,2009,30(10):2908-2916.
[8]肖桃李,李新平,贾善坡.深部单裂隙岩体结构面效应的三轴试验研究与力学分析[J].岩石力学与工程学报,2012,31(8):1666-1673.XIAO Tao-li,LI Xin-ping,JIA Shan-po.Triaxial test research and mechanical analysis based on structure surface effect of deep rock mass with single fissure[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(8):1666-1673.
[9]REIK G,ZACAS M.Strength and deformation characteristics of jointed media in true triaxial compression[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1978,15(6):295-303.
[10]杨圣奇,陆家炜,田文岭,等.不同节理粗糙度类岩石材料三轴压缩力学特性试验研究[J].岩土力学,2018,39(增刊1):21-32.YANG Sheng-qi,LU Jia-wei,TIAN Wen-ling,et al.Experimental study of mechanical behavior of rock specimens with different joint roughness coefficient under conventional triaxial compression[J].Rock and Soil Mechanics,2018,(Suppl.1):21-32.
[11]NASSERI M H,RAO K S,RAMAMURTHY T.Failure mechanism in schistose rocks[J].International Journal of Rock Mechanics&Mining Sciences,1997,34(3-4):460-460.
[12]ARZúA J,ALEJANO L R,WALTON G.Strength and dilation of jointed granite specimens in servo-controlled triaxial tests[J].International Journal of Rock Mechanics&Mining Sciences,2014,69(3):93-104.
[13]MEDHURST T P,BROWN E T.A study of the mechanical behaviour of coal for pillar design[J].International Journal of Rock Mechanics&Mining Sciences,1998,35(8):1087-1105.
[14]LIU M,LIU E.Dynamic mechanical properties of artificial jointed rock samples subjected to cyclic triaxial loading[J].International Journal of Rock Mechanics&Mining Sciences,2017,98(1):54-66.
[15]南京水利科学研究院.SL327-1999土工试验规程[S].北京:中国水利水电出版社,1999.Nanjing Hydraulic Research Institute.SL327-1999Rules of Geotechnical Testing[S].Beijing:China Water&Power Press,1999.
[16]CHO J W,KIM H,JEON S,et al.Deformation and strength anisotropy of Asan gneiss,Boryeong shale,and Yeoncheon schist[J].International Journal of Rock Mechanics&Mining Sciences,2012,50(2):158-169.
[17]XIAO W,DENG R,ZHONG Z,et al.Experimental study on the mechanical properties of simulated columnar jointed rock masses[J].Journal of Geophysics&Engineering,2015,12(1):80-89.
[18]耶格尔J C,库克N G W.岩石力学基础[M].中国科学院工程力学研究所译.北京:科学出版社,1981.JAEGER J C,COOK N G W.Fundamentals of rock mechanics[M].Translated by Institute of Mechanics,Chinese Academy of Sciences.Beijing:Science Press,1981.
[19]DONATH F A.Experimental study of shear failure in anisotropic rocks[J].Geological Society of America Bulletin,1961,72(6):985-989.
[20]SINGH M,RAO K S,RAMAMURTHY T.Strength and deformational behaviour of a jointed rock mass[J].Rock Mechanics&Rock Engineering,2002,35(1):45-64.
[21]张永兴,许明.岩石力学[M].北京:中国建筑工业出版社,2015.ZHANG Yong-xing,XU Ming.Rock mechanics[M].Beijing:China Architecture&Building Press,2015
[22]孙广忠.岩体力学原理[M].北京:科学出版社,2011.SUN Guang-zhong.Principle of rock mass mechanics[M].Beijing:Science Press,2011.
[23]HOEK E,BROWN E T,The Hoek-Brown failure criterion and GSI[J/OL].Journal of Rock Mechanics and Geotechnical Engineering,[2018-07-01].https://doi.org/10.1016/j.jrmge.2018.08.001.
[24]HOEK E.Strength of jointed rock masses[J].Géotechnique,1983,33(33):187-223.
[25]JAEGER J C,COOK N G W.Fundamentals of rock mechanics[M].London:Chapman and Hall,1969.
[26]韩建新,李术才,李树忱,等.贯穿裂隙岩体强度和破坏方式的模型研究[J].岩土力学,2011,32(增刊2):178-184.HAN Jian-xin,LI Shu-cai,LI Shu-chen,et al.Model study of strength and failure modes of rock mass with persistent cracks[J].Rock and Soil Mechanics,2011,32(Suppl.2):178-184.