考虑渗透吸力影响膨润土的修正有效应力及其验证
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摘要
普遍认为膨润土是高放废物地质处置库缓冲/回填层的理想材料,膨润土在地下水溶液中的膨胀变形和剪切强度关乎高放废物地质处置库的安危。地下水溶液中膨润土膨胀变形和剪切强度受到渗透吸力影响,根据膨润土表面分形模型,建立考虑渗透吸力应力影响的修正有效应力公式,用竖向应力p和渗透吸力π表示为■,并采用膨润土在NaCl溶液中的膨胀变形和剪切强度进行验证。NaCl溶液中膨润土的膨胀变形与修正有效应力p~e表示为同一曲线■,峰值剪切强度与修正有效应力p~e表示为同一直线■,符合Mohr–Coulomb准则。
Bentonite is widely seen as a potential buffer/backfill materials for deeply buried geological disposal system to isolate high-level radioactive waste(HLRW). The swelling deformation and shear strength of the bentonite in saline solutions are very important to the safety of the HLRW depository. A conceptual model is proposed to explain the influences of osmotic suction on the volume change and shear strength of the bentonite in a quantitative way. A new formula for the effective stress is proposed as ■ incorporating with vertical stress(p) and osmotic suction(π), and ■. The e _m-p~e relationship is expressed using a unique curve in the form of ■ for the bentonite in NaCl solutions. The peak shear strength is expressed using a unique curve according to the Mohr–Coulomb criterion for the bentonite in NaCl solutions.
Bentonite is widely seen as a potential buffer/backfill materials for deeply buried geological disposal system to isolate high-level radioactive waste(HLRW). The swelling deformation and shear strength of the bentonite in saline solutions are very important to the safety of the HLRW depository. A conceptual model is proposed to explain the influences of osmotic suction on the volume change and shear strength of the bentonite in a quantitative way. A new formula for the effective stress is proposed as ■ incorporating with vertical stress(p) and osmotic suction(π), and ■. The e _m-p~e relationship is expressed using a unique curve in the form of ■ for the bentonite in NaCl solutions. The peak shear strength is expressed using a unique curve according to the Mohr–Coulomb criterion for the bentonite in NaCl solutions.
引文
[1]XU Y F,MATSUOKA H,SUN D A.Swelling characteristics of fractal-textured bentonite and its mixture[J].Appl Clay Sci,2003,22:197-209.
[2]秦冰,陈正汉,刘月妙,等.高庙子膨润土的胀缩变形特性及其影响因素[J].岩土工程学报,2008,30(7):1005-1010.(QIN Bing,CHEN Zheng-han,LIU Yue-miao,et al.Swelling-shrinkage behaviour of Gaomiaozi bentonite[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1005-1010.(in Chinese))
[3]叶为民,黄伟,陈宝,等.双电层理论与高庙子膨润土的体变特征[J].岩土力学,2009,30(7):1899-1904.(YEWei-min,HUANG Wei,CHEN Bao,et al.Diffuse double layer theory and volume change behavior of densely compacted Gaomiaozi bentonite[J].Rock and Soil Mechanics,2009,30(7):1899-1904.(in Chinese))
[4]孙德安,张龙.盐溶液饱和高庙子膨润土膨胀特性及预测[J].岩土力学,2013,34(10):2790-2795.(SUN De-an,ZHANG Long.Swelling characteristics of Gaomiaozi bentonite saturated by salt solution and their prediction[J].Rock and Soil Mechanics,2013,34(10):2790-2795.(in Chinese))
[5]张虎元,贾灵艳,周浪.高效废物处置库的混合型缓冲回填材料压缩特性研究[J].岩土力学,2013,34(6):1546-1552.(ZHANG Hu-yuan,JIA Ling-yan,ZHOU Lang.Compression behaviors of compacted bentonite-sand mixtures as buffer material for HLW disposal[J].Rock and Soil Mechanics,2013,34(6):1546-1552.(in Chinese))
[6]YE W M,WAN M,CHEN B,et al.Temperature effects on the unsaturated permeability of the densely compacted GMZ01bentonite under confined conditions[J].Eng Geol,2012,126:1-7.
[7]XU Y F,DONG P.Fractal approach to hydraulic properties in unsaturated porous media[J].Chaos,Solitons and Fractals,2004,19:327-337.
[8]谭罗荣,孔令伟.膨胀土膨胀特性的变化规律研究[J].岩土力学,2004,25(10):1555-1559.(TAN Lou-rong,KONGLing-wei.Study on variation regularity of swelling behavior of expansive soil[J].Soil Mechanics,2004,25(10):1555-1559.(in Chinese))
[9]姜昊,徐永福,项国圣.膨润土在核废料处置环境中的膨胀衰减规律研究[J].工程地质学报,2014,22(2):203-209.(JIANG Hao,XU Yong-fu,XIANG Guo-sheng.Numerical simulation for decay of swelling capacity of bentonite in high-level nuclear waste repository[J].Journal of Engineering Geology,2014,22(2):203-209.(in Chinese))
[10]孙文静,刘仕卿,孙德安.高掺砂率膨润土混合土膨胀特性及其膨胀量预测[J].岩土工程学报,2015,37(9):1620-1626.(SUN Wen-jing,LIU Shi-qing,SUN De-an,et al.Swelling characteristics of bentonite-sand mixtures with a high sand mixing ratio and its prediction[J].Chinese Journal of Geotechnical Engineering,2015,37(9):1620-1626.(in Chinese))
[11]项国圣,徐永福,姜昊.压实膨润土在盐溶液中的膨胀变形特性[J].工程地质学报,2015,23(6):1053-1058.(XIANG Guo-sheng,XU Yong-fu,JIANG Hao.Swelling behavior of compacted bentonite under osmotic suction[J].Journal of Engineering Geology,2015,23(6):1053-1058.(in Chinese))
[12]STUDDS P G,STEWART D I,COUSENS T W.The effects of salt solutions on the properties of bentonite-sand mixtures[J].Clay Miner,1998,33:651-661.
[13]DI Maio C,SANTOLI L,SCHIAVONE P.Volume change behaviour of clays:the influence of mineral composition,pore fluid composition and stress state[J].Mech Mater,2004,36:435-451.
[14]CALVELLO M,LASCO M,VASSALLO R,et al.Compressibility and residual shear strength of smectitic clays:influence of pore aqueous solutions and organic solvents[J].Riv Ital Geotec,2005,1:34-46.
[15]YE W M,ZHANG F,CHEN B,et al.Effects of salt solutions on the hydro-mechanical behavior of compacted GMZ01bentonite[J].Environ Earth Sci,2014,72:2621-2630.
[16]LORET B,KHALILI N.An effective stress elasto-plastic model for unsaturated soils[J].Mech Mater,2002,44:97-116.
[17]XU Y,XIANG G S,JINAG H,et al.Role of osmotic suction in volume change of clays in salt solution[J].Appl Clay Sci,2014,101:354-361.
[18]MITCHELL J K,SOGA K.Fundamentals of soil behavior[M].3rd ed.New York:Wiley,2005.
[19]DI MAIO C.Shear strength of clays and clayey soils:the influence of pore fluid composition[C]//Chemo-Mechanical Couplings in Porous Media Geomechanics and Biomechanics.LORET B,HUYGHE L,eds.Springer-Verlag Wien NY,2004.
[20]DI MAIO C,SANTOLI L,SCHIAVONE P.Volume change behaviour of clays:the influence of mineral composition,pore fluid composition and stress state[J].Mech of Maters,2004,36:435-451.
[21]CALVELLO M,LASCO M,VASSALLO R,et al.Compressibility and residual shear strength of smectitic clays:influence of pore aqueous solutions and organic solvents[J].Rivista Italiana Di Geotechnica,2005,1:33-46.
[22]WINTERKORN H F,MOORMAN R B B.A study of changes in physical properties of Putnam soil induced by ionic substitution[J].Proc Highways Res Board,1941,21:415-434.
[23]BULUT R,LYTTON R L,WRAY W K.Suction measurements by filter paper,expansive clay soils and vegetative influence on shallow foundations[C]//VIPULANANDAN C,ADISON M B,HASEN M,eds.Geotechnical Publication,ASCE.Reston,VA,2001.
[24]MAN A,GRAHAM J,VAN Gulck J.Effect of pore fluid chemistry on strain-softening behaviour of reconstituted plastic clay[C]//Procs of the Int Cong on Envir Geotech.Cardiff,2006:569-576.
[25]TIWARI B,AJMERA B.A new correlation relating the shear strength of reconstituted soil to the proportions of clay minerals and plasticity characteristics[J].Appl Clay Sci,2011,53:48-57.
[26]ZHANG L,SUN D A,JIA D.Shear strength of GMZ07bentonite and its mixture with sand saturated with saline solution[J].Appl Clay Sci,2016(132/133):24-32.
[27]XU Y F,SUN D A,YAO Y P.Surface fractal dimension of bentonite and its application to determination of swelling properties[J].Chaos,Solitons and Fractals,2004,19:347-356.
[28]METTEN U.Desalination by reverse osmosis[J].Cambridge:MIT Press,1966.
[29]SPOSITO G.The thermodynamic of soil solution[M].London:Oxford Clarendon Press,1981.
[30]LANG A R G.Osmotic coefficients and water potentials of sodium chloride solution from 0 to 40℃[J].Australian J of Chem,1967,20:2017-2023.
[31]MESRI G,OLSON R E.Shear strength of montmorillonite[J].Géotechnique,1970,3:261-270.
[32]AVNIR D,JARONIEC M.An isotherm equation for adsorption on fractal surfaces of heterogeneous porous materials[J].Langmuir,1989,5:1431-1433.
[33]SUN W J,WE Z F,LIU S Q,et al.Deformation characteristics and permeability of saturated bentonite-sand mixtures[C]//Unsaturated Soil Mechanics from Theory to Practice(AP-UNSAT 2015).Gulin,2015.
[34]COKCA E,TILGEN H P.Shear strength-suction relationship of compacted Ankara clay[J].Appl Clay Sci,2010,49:400-404.
[35]BLATZ J A,GRAHAM J,CHANDLER N A.Influence of suction on the strength and stiffness of compacted sand-bentonite[J].Can Geotech J,2002,39:1005-1015.
[36]DI Maio C.Exposure of bentonite to salt solution:osmotic and mechanical effects[J].Géotechnique,1996,46(4):695-707.
[37]XU Y F.Fractal model for the correlation relating total suction to water content of bentonites[J].Fractals,2017.(in press)
[38]KENNEY T C.The influence of mineralogical composition on the residual strength of natural soils[C]//Procs of the Geotech Conf on Shear Strength Properties of Natural Soils and Rocks.Oslo,1967.
[39]SKEMPTON A W.Residual strength of clays in landslides folded strata and the laboratory[J].Géotechnique,1985,35(1):3-18.
[40]BURLAND J B.On the compressibility and shear strength of natural clays[J].Géotechnique,1990,40(3):329-378.
[41]WIEBE B,GRAHAM J,DIXON D.Influence of pressure,saturation and temperature on the behavior of unsaturated sand-bentonite[J].Cana Geotech J,1998,35:194-205.
[42]TANG G X.Suction characteristics and elastic-plastic modelling of unsaturated sand-bentonite mixture[D].Manitob a:University of Manitoba,1999.
[43]BLATZ J A,GRAHAM J,CHANDLER N A.Influence of suction on the strength and stiffness of compacted sand-bentonite[J].Can Geotech J,2002,39:1005-1015.
[2]秦冰,陈正汉,刘月妙,等.高庙子膨润土的胀缩变形特性及其影响因素[J].岩土工程学报,2008,30(7):1005-1010.(QIN Bing,CHEN Zheng-han,LIU Yue-miao,et al.Swelling-shrinkage behaviour of Gaomiaozi bentonite[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1005-1010.(in Chinese))
[3]叶为民,黄伟,陈宝,等.双电层理论与高庙子膨润土的体变特征[J].岩土力学,2009,30(7):1899-1904.(YEWei-min,HUANG Wei,CHEN Bao,et al.Diffuse double layer theory and volume change behavior of densely compacted Gaomiaozi bentonite[J].Rock and Soil Mechanics,2009,30(7):1899-1904.(in Chinese))
[4]孙德安,张龙.盐溶液饱和高庙子膨润土膨胀特性及预测[J].岩土力学,2013,34(10):2790-2795.(SUN De-an,ZHANG Long.Swelling characteristics of Gaomiaozi bentonite saturated by salt solution and their prediction[J].Rock and Soil Mechanics,2013,34(10):2790-2795.(in Chinese))
[5]张虎元,贾灵艳,周浪.高效废物处置库的混合型缓冲回填材料压缩特性研究[J].岩土力学,2013,34(6):1546-1552.(ZHANG Hu-yuan,JIA Ling-yan,ZHOU Lang.Compression behaviors of compacted bentonite-sand mixtures as buffer material for HLW disposal[J].Rock and Soil Mechanics,2013,34(6):1546-1552.(in Chinese))
[6]YE W M,WAN M,CHEN B,et al.Temperature effects on the unsaturated permeability of the densely compacted GMZ01bentonite under confined conditions[J].Eng Geol,2012,126:1-7.
[7]XU Y F,DONG P.Fractal approach to hydraulic properties in unsaturated porous media[J].Chaos,Solitons and Fractals,2004,19:327-337.
[8]谭罗荣,孔令伟.膨胀土膨胀特性的变化规律研究[J].岩土力学,2004,25(10):1555-1559.(TAN Lou-rong,KONGLing-wei.Study on variation regularity of swelling behavior of expansive soil[J].Soil Mechanics,2004,25(10):1555-1559.(in Chinese))
[9]姜昊,徐永福,项国圣.膨润土在核废料处置环境中的膨胀衰减规律研究[J].工程地质学报,2014,22(2):203-209.(JIANG Hao,XU Yong-fu,XIANG Guo-sheng.Numerical simulation for decay of swelling capacity of bentonite in high-level nuclear waste repository[J].Journal of Engineering Geology,2014,22(2):203-209.(in Chinese))
[10]孙文静,刘仕卿,孙德安.高掺砂率膨润土混合土膨胀特性及其膨胀量预测[J].岩土工程学报,2015,37(9):1620-1626.(SUN Wen-jing,LIU Shi-qing,SUN De-an,et al.Swelling characteristics of bentonite-sand mixtures with a high sand mixing ratio and its prediction[J].Chinese Journal of Geotechnical Engineering,2015,37(9):1620-1626.(in Chinese))
[11]项国圣,徐永福,姜昊.压实膨润土在盐溶液中的膨胀变形特性[J].工程地质学报,2015,23(6):1053-1058.(XIANG Guo-sheng,XU Yong-fu,JIANG Hao.Swelling behavior of compacted bentonite under osmotic suction[J].Journal of Engineering Geology,2015,23(6):1053-1058.(in Chinese))
[12]STUDDS P G,STEWART D I,COUSENS T W.The effects of salt solutions on the properties of bentonite-sand mixtures[J].Clay Miner,1998,33:651-661.
[13]DI Maio C,SANTOLI L,SCHIAVONE P.Volume change behaviour of clays:the influence of mineral composition,pore fluid composition and stress state[J].Mech Mater,2004,36:435-451.
[14]CALVELLO M,LASCO M,VASSALLO R,et al.Compressibility and residual shear strength of smectitic clays:influence of pore aqueous solutions and organic solvents[J].Riv Ital Geotec,2005,1:34-46.
[15]YE W M,ZHANG F,CHEN B,et al.Effects of salt solutions on the hydro-mechanical behavior of compacted GMZ01bentonite[J].Environ Earth Sci,2014,72:2621-2630.
[16]LORET B,KHALILI N.An effective stress elasto-plastic model for unsaturated soils[J].Mech Mater,2002,44:97-116.
[17]XU Y,XIANG G S,JINAG H,et al.Role of osmotic suction in volume change of clays in salt solution[J].Appl Clay Sci,2014,101:354-361.
[18]MITCHELL J K,SOGA K.Fundamentals of soil behavior[M].3rd ed.New York:Wiley,2005.
[19]DI MAIO C.Shear strength of clays and clayey soils:the influence of pore fluid composition[C]//Chemo-Mechanical Couplings in Porous Media Geomechanics and Biomechanics.LORET B,HUYGHE L,eds.Springer-Verlag Wien NY,2004.
[20]DI MAIO C,SANTOLI L,SCHIAVONE P.Volume change behaviour of clays:the influence of mineral composition,pore fluid composition and stress state[J].Mech of Maters,2004,36:435-451.
[21]CALVELLO M,LASCO M,VASSALLO R,et al.Compressibility and residual shear strength of smectitic clays:influence of pore aqueous solutions and organic solvents[J].Rivista Italiana Di Geotechnica,2005,1:33-46.
[22]WINTERKORN H F,MOORMAN R B B.A study of changes in physical properties of Putnam soil induced by ionic substitution[J].Proc Highways Res Board,1941,21:415-434.
[23]BULUT R,LYTTON R L,WRAY W K.Suction measurements by filter paper,expansive clay soils and vegetative influence on shallow foundations[C]//VIPULANANDAN C,ADISON M B,HASEN M,eds.Geotechnical Publication,ASCE.Reston,VA,2001.
[24]MAN A,GRAHAM J,VAN Gulck J.Effect of pore fluid chemistry on strain-softening behaviour of reconstituted plastic clay[C]//Procs of the Int Cong on Envir Geotech.Cardiff,2006:569-576.
[25]TIWARI B,AJMERA B.A new correlation relating the shear strength of reconstituted soil to the proportions of clay minerals and plasticity characteristics[J].Appl Clay Sci,2011,53:48-57.
[26]ZHANG L,SUN D A,JIA D.Shear strength of GMZ07bentonite and its mixture with sand saturated with saline solution[J].Appl Clay Sci,2016(132/133):24-32.
[27]XU Y F,SUN D A,YAO Y P.Surface fractal dimension of bentonite and its application to determination of swelling properties[J].Chaos,Solitons and Fractals,2004,19:347-356.
[28]METTEN U.Desalination by reverse osmosis[J].Cambridge:MIT Press,1966.
[29]SPOSITO G.The thermodynamic of soil solution[M].London:Oxford Clarendon Press,1981.
[30]LANG A R G.Osmotic coefficients and water potentials of sodium chloride solution from 0 to 40℃[J].Australian J of Chem,1967,20:2017-2023.
[31]MESRI G,OLSON R E.Shear strength of montmorillonite[J].Géotechnique,1970,3:261-270.
[32]AVNIR D,JARONIEC M.An isotherm equation for adsorption on fractal surfaces of heterogeneous porous materials[J].Langmuir,1989,5:1431-1433.
[33]SUN W J,WE Z F,LIU S Q,et al.Deformation characteristics and permeability of saturated bentonite-sand mixtures[C]//Unsaturated Soil Mechanics from Theory to Practice(AP-UNSAT 2015).Gulin,2015.
[34]COKCA E,TILGEN H P.Shear strength-suction relationship of compacted Ankara clay[J].Appl Clay Sci,2010,49:400-404.
[35]BLATZ J A,GRAHAM J,CHANDLER N A.Influence of suction on the strength and stiffness of compacted sand-bentonite[J].Can Geotech J,2002,39:1005-1015.
[36]DI Maio C.Exposure of bentonite to salt solution:osmotic and mechanical effects[J].Géotechnique,1996,46(4):695-707.
[37]XU Y F.Fractal model for the correlation relating total suction to water content of bentonites[J].Fractals,2017.(in press)
[38]KENNEY T C.The influence of mineralogical composition on the residual strength of natural soils[C]//Procs of the Geotech Conf on Shear Strength Properties of Natural Soils and Rocks.Oslo,1967.
[39]SKEMPTON A W.Residual strength of clays in landslides folded strata and the laboratory[J].Géotechnique,1985,35(1):3-18.
[40]BURLAND J B.On the compressibility and shear strength of natural clays[J].Géotechnique,1990,40(3):329-378.
[41]WIEBE B,GRAHAM J,DIXON D.Influence of pressure,saturation and temperature on the behavior of unsaturated sand-bentonite[J].Cana Geotech J,1998,35:194-205.
[42]TANG G X.Suction characteristics and elastic-plastic modelling of unsaturated sand-bentonite mixture[D].Manitob a:University of Manitoba,1999.
[43]BLATZ J A,GRAHAM J,CHANDLER N A.Influence of suction on the strength and stiffness of compacted sand-bentonite[J].Can Geotech J,2002,39:1005-1015.