应变敏感的裂隙及裂隙岩体水力传导特性研究
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摘要
通过将岩体单裂隙视为非关联理想弹塑性体,导出单裂隙在压剪荷载作用下,其机械开度和水力传导度的解析模型,并采用已有相关试验研究成果对解析模型进行验证。在此基础上,通过将岩体概化为含一组或多组优势裂隙的等效连续介质,给出一种描述裂隙岩体在复杂加载条件下考虑非线性变形特征及滑动剪胀特性的等效非关联理想弹塑性本构模型。基于该模型,给出裂隙岩体在扰动条件下应变敏感的渗透张量的计算方法,该计算方法不仅考虑裂隙的法向压缩变形,而且反映材料非线性及峰后剪胀效应对裂隙岩体渗透特性的影响。该模型通过引入滑动剪胀角和非关联理想塑性,较为逼真地反映了真实裂隙及裂隙岩体峰后的剪胀特性、变形行为和水力传导度变化特征。通过数值算例,研究了裂隙岩体在力学加载及开挖条件下渗透特性的演化规律。
Regarding single rock fracture as a non-associated elastic-perfectly plastic medium,an analytical model of the mechanical aperture and the hydraulic conductivity is developed for the fracture subjected to normal and shear loadings,and the model is validated by an existing shear-flow coupling test under wide range of constant normal stress and increasing shear displacement.On this basis,by regarding rock mass as an anisotropic continuum with one or multiple sets of critically oriented fractures,a methodology is developed to address the change in hydraulic conductivity resulted from engineering disturbance under the framework of material nonlinearity.An equivalent non-associated elastic-perfectly plastic constitutive model with mobilized dilatancy is presented to describe the global nonlinear response of the rock system under complex loading conditions.By resolving the deformation of fractures from the equivalent medium,a strain-dependent hydraulic conductivity tensor suitable for numerical analysis is formulated,where the normal compressive deformations of the fractures are considered;and more importantly,the effects of material nonlinearity and post-peak shear dilatancy are integrated.The proposed model is capable of describing the reality of the post-peak dilatancy behavior,deformation characteristic and changes in hydraulic conductivity of a real fracture and fractured rock mass by using non-associated flow rule with a mobilized dilatancy angle.Numerical simulations are performed to investigate the changes in hydraulic conductivities of rock masses under mechanical loading or excavation.
Regarding single rock fracture as a non-associated elastic-perfectly plastic medium,an analytical model of the mechanical aperture and the hydraulic conductivity is developed for the fracture subjected to normal and shear loadings,and the model is validated by an existing shear-flow coupling test under wide range of constant normal stress and increasing shear displacement.On this basis,by regarding rock mass as an anisotropic continuum with one or multiple sets of critically oriented fractures,a methodology is developed to address the change in hydraulic conductivity resulted from engineering disturbance under the framework of material nonlinearity.An equivalent non-associated elastic-perfectly plastic constitutive model with mobilized dilatancy is presented to describe the global nonlinear response of the rock system under complex loading conditions.By resolving the deformation of fractures from the equivalent medium,a strain-dependent hydraulic conductivity tensor suitable for numerical analysis is formulated,where the normal compressive deformations of the fractures are considered;and more importantly,the effects of material nonlinearity and post-peak shear dilatancy are integrated.The proposed model is capable of describing the reality of the post-peak dilatancy behavior,deformation characteristic and changes in hydraulic conductivity of a real fracture and fractured rock mass by using non-associated flow rule with a mobilized dilatancy angle.Numerical simulations are performed to investigate the changes in hydraulic conductivities of rock masses under mechanical loading or excavation.
引文
[1]Jing L.A review of techniques,advances and outstanding issues in numerical modeling for rock mechanics and rock engineering[J].International Journal of Rock Mechanics and Mining Sciences,2003,40(3):283–353.
[2]Louis C.Rock Hydraulics[A].In:Muller L ed.Rock Mechanics[C].New York:Verlay Wien,1974.287–299.
[3]Kranz R L,Frankel A D,Engelder T,et al.The permeability of whole and jointed Barre granite[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1979,16(2):225–234.
[4]Jones F O.A laboratory study of the effects of confining pressure on fracture flow and storage capacity in carbonate rocks[J].Journal of Petrol Technology,1975,9(2):21–27.
[5]Nelson R A.Fracture permeability in porous reservoirs:an experimental and field approach[Ph.D.Thesis][D].Texas:Department of Geology,Texas A and M University,1975.
[6]张玉卓,张金才.裂隙岩体渗流与应力耦合的试验研究[J].岩土力学,1997,18(4):59–62.(Zhang Yuzhuo,Zhang Jincai.Experimental study on seepage flow-stress coupling in fractured rock masses[J].Rock and Soil Mechanics,1997,18(4):59–62.(in Chinese))
[7]郑少河,赵阳升,段康廉.三维应力作用下天然裂隙渗流规律的试验研究[J].岩石力学与工程学报,1999,18(2):133–136.(Zheng Shaohe,Zhao Yangsheng,Duan Kanglian.An experimental study on permeability law of natural fracture under3D stresses[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(2):133–136.(in Chinese))
[8]刘亚晨,蔡永庆,刘泉声,等.岩体裂隙结构面的温度–水力–应力耦合本构关系[J].岩土工程学报,2001,23(2):196–200.(Liu Yachen,Cai Yongqing,Liu Quansheng,et al.Thermo-hydro-mechanical coupling constitutive relation of rock mass fracture interconnectivity[J].Chinese Journal of Geotechnical Engineering,2001,23(2):196–200.(in Chinese))
[9]Esaki T,Du S,Mitani Y,et al.Development of a shear-flow test apparatus and determination of coupled properties for a single rock joint[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1999,36(5):641–650.
[10]Chen Z,Narayan S P,Yang Z.An experimental investigation of hydraulic behavior of fractures and joints in granitic rock[J].International Journal of Rock Mechanics and Mining Sciences,2000,37(7):1061–1071.
[11]刘才华,陈从新,付少兰.剪应力作用下岩体裂隙渗流特性研究[J].岩石力学与工程学报,2003,22(10):1651–1655.(Liu Caihua,Chen Congxin,Fu Shaolan.Study on seepage characteristics of a single rock fracture under shear stresses[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(10):1651–1655.(in Chinese))
[12]刘才华,陈从新,付少兰.二维应力作用下岩石单裂隙渗流规律的试验研究[J].岩石力学与工程学报,2002,21(8):1194–1198.(Liu Caihua,Chen Congxin,Fu Shaolan.Testing study on seepage characteristic of a single rock fracture under two-dimensional stresses[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(8):1194–1198.(in Chinese))
[13]周创兵,熊文林.地应力对岩体渗透特性的影响[J].地震学报,1997,19(2):154–163.(Zhou Chuangbing,Xiong Wenlin.Influence of geostatic stresses on permeability of jointed rock masses[J].Acta Seismologica Sinica,1997,19(2):154–163.(in Chinese))
[14]Snow D T.Anisotropic permeability of fractured media[J].Water Resources Research,1969,5(6):1273–1289.
[15]Oda M.An equivalent continuum model for coupled stress and fluid flow analysis in jointed rock masses[J].Water Resources Research,1986,22(13):1845–1856.
[16]周创兵,熊文林.双场耦合条件下裂隙岩体的渗透张量[J].岩石力学与工程学报,1996,15(4):338–344.(Zhou Chuangbing,XiongWenlin.Permeability tensor for jointed rock mass in coupled seepage and stress fields[J].Chinese Journal of Rock Mechanics and Engineering,1996,15(4):338–344.(in Chinese))
[17]Liu J,Elsworth D,Brady B H.Linking stress-dependent effective porosity and hydraulic conductivity fields to RMR[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1999,36(5):581–596.
[18]Huang T H,Chang C S,Chao C Y.Experimental and mathematical modeling for fracture of rock joint with regular asperities[J].Engineering Fracture Mechanics,2002,69(17):1977–1996.
[19]Alejano L R,Alonso E.Consideration of the dilatancy angle in rocks and rock masses[J].International Journal of Rock Mechanics and Mining Sciences,2005,42(4):481–507.
[20]Barton N,Bandis S C.Effects of block size on the shear behaviour of jointed rocks[A].In:Proceedings of the23rd US Symposium on Rock Mechanics[C].Rotterdam:A.A.Balkema,1982.739–760.
[21]Zhou C B,Chen Y F,Sheng Y Q.A generalized cubic law for rock joints considering post-peak mechanical effects[A].In:Proceedings of GeoProc2006[C].Nanjing:Hohai University Press,2006.188–197.
[22]Barton N,Bandis S,Bakhtar K.Strength,deformation and conductivity coupling of rock joints[J].International Journal of Rock Mechanics and Mining Sciences,1985,22(3):121–140.
[23]Pande G N,Xiong W L.An improved multilaminate model of jointed rock masses[A].In:Dungar R,Pande GN,Studer JA,ed.Proceedings of Numerical Models in Geomechanics[C].Rotterdam:A.A.Balkema,1982.218–226.
[24]Chen S H,Egger P.Three-dimensional elasto-visco-plastic finite element analysis of reinforced rock masses and its application[J].International Journal for Numerical Analytical Methods in Geomechanics,1999,23(1):61–78.
[25]Pusch R.Alteration of the hydraulic conductivity of rock by tunnel excavation[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1989,26(1):79–83.
[26]Kelsall P C,Case J B,Chabannes C R.Evaluation of excavation-induced changes in rock permeability[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1984,21(3):123–135.
[2]Louis C.Rock Hydraulics[A].In:Muller L ed.Rock Mechanics[C].New York:Verlay Wien,1974.287–299.
[3]Kranz R L,Frankel A D,Engelder T,et al.The permeability of whole and jointed Barre granite[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1979,16(2):225–234.
[4]Jones F O.A laboratory study of the effects of confining pressure on fracture flow and storage capacity in carbonate rocks[J].Journal of Petrol Technology,1975,9(2):21–27.
[5]Nelson R A.Fracture permeability in porous reservoirs:an experimental and field approach[Ph.D.Thesis][D].Texas:Department of Geology,Texas A and M University,1975.
[6]张玉卓,张金才.裂隙岩体渗流与应力耦合的试验研究[J].岩土力学,1997,18(4):59–62.(Zhang Yuzhuo,Zhang Jincai.Experimental study on seepage flow-stress coupling in fractured rock masses[J].Rock and Soil Mechanics,1997,18(4):59–62.(in Chinese))
[7]郑少河,赵阳升,段康廉.三维应力作用下天然裂隙渗流规律的试验研究[J].岩石力学与工程学报,1999,18(2):133–136.(Zheng Shaohe,Zhao Yangsheng,Duan Kanglian.An experimental study on permeability law of natural fracture under3D stresses[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(2):133–136.(in Chinese))
[8]刘亚晨,蔡永庆,刘泉声,等.岩体裂隙结构面的温度–水力–应力耦合本构关系[J].岩土工程学报,2001,23(2):196–200.(Liu Yachen,Cai Yongqing,Liu Quansheng,et al.Thermo-hydro-mechanical coupling constitutive relation of rock mass fracture interconnectivity[J].Chinese Journal of Geotechnical Engineering,2001,23(2):196–200.(in Chinese))
[9]Esaki T,Du S,Mitani Y,et al.Development of a shear-flow test apparatus and determination of coupled properties for a single rock joint[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1999,36(5):641–650.
[10]Chen Z,Narayan S P,Yang Z.An experimental investigation of hydraulic behavior of fractures and joints in granitic rock[J].International Journal of Rock Mechanics and Mining Sciences,2000,37(7):1061–1071.
[11]刘才华,陈从新,付少兰.剪应力作用下岩体裂隙渗流特性研究[J].岩石力学与工程学报,2003,22(10):1651–1655.(Liu Caihua,Chen Congxin,Fu Shaolan.Study on seepage characteristics of a single rock fracture under shear stresses[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(10):1651–1655.(in Chinese))
[12]刘才华,陈从新,付少兰.二维应力作用下岩石单裂隙渗流规律的试验研究[J].岩石力学与工程学报,2002,21(8):1194–1198.(Liu Caihua,Chen Congxin,Fu Shaolan.Testing study on seepage characteristic of a single rock fracture under two-dimensional stresses[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(8):1194–1198.(in Chinese))
[13]周创兵,熊文林.地应力对岩体渗透特性的影响[J].地震学报,1997,19(2):154–163.(Zhou Chuangbing,Xiong Wenlin.Influence of geostatic stresses on permeability of jointed rock masses[J].Acta Seismologica Sinica,1997,19(2):154–163.(in Chinese))
[14]Snow D T.Anisotropic permeability of fractured media[J].Water Resources Research,1969,5(6):1273–1289.
[15]Oda M.An equivalent continuum model for coupled stress and fluid flow analysis in jointed rock masses[J].Water Resources Research,1986,22(13):1845–1856.
[16]周创兵,熊文林.双场耦合条件下裂隙岩体的渗透张量[J].岩石力学与工程学报,1996,15(4):338–344.(Zhou Chuangbing,XiongWenlin.Permeability tensor for jointed rock mass in coupled seepage and stress fields[J].Chinese Journal of Rock Mechanics and Engineering,1996,15(4):338–344.(in Chinese))
[17]Liu J,Elsworth D,Brady B H.Linking stress-dependent effective porosity and hydraulic conductivity fields to RMR[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1999,36(5):581–596.
[18]Huang T H,Chang C S,Chao C Y.Experimental and mathematical modeling for fracture of rock joint with regular asperities[J].Engineering Fracture Mechanics,2002,69(17):1977–1996.
[19]Alejano L R,Alonso E.Consideration of the dilatancy angle in rocks and rock masses[J].International Journal of Rock Mechanics and Mining Sciences,2005,42(4):481–507.
[20]Barton N,Bandis S C.Effects of block size on the shear behaviour of jointed rocks[A].In:Proceedings of the23rd US Symposium on Rock Mechanics[C].Rotterdam:A.A.Balkema,1982.739–760.
[21]Zhou C B,Chen Y F,Sheng Y Q.A generalized cubic law for rock joints considering post-peak mechanical effects[A].In:Proceedings of GeoProc2006[C].Nanjing:Hohai University Press,2006.188–197.
[22]Barton N,Bandis S,Bakhtar K.Strength,deformation and conductivity coupling of rock joints[J].International Journal of Rock Mechanics and Mining Sciences,1985,22(3):121–140.
[23]Pande G N,Xiong W L.An improved multilaminate model of jointed rock masses[A].In:Dungar R,Pande GN,Studer JA,ed.Proceedings of Numerical Models in Geomechanics[C].Rotterdam:A.A.Balkema,1982.218–226.
[24]Chen S H,Egger P.Three-dimensional elasto-visco-plastic finite element analysis of reinforced rock masses and its application[J].International Journal for Numerical Analytical Methods in Geomechanics,1999,23(1):61–78.
[25]Pusch R.Alteration of the hydraulic conductivity of rock by tunnel excavation[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1989,26(1):79–83.
[26]Kelsall P C,Case J B,Chabannes C R.Evaluation of excavation-induced changes in rock permeability[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1984,21(3):123–135.
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