盐溶液饱和黏土的等向压缩特性
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摘要
利用不同浓度Na Cl溶液饱和黏土,进行等向压缩试验并分析渗透吸力对等向压缩特性的影响规律。试验结果表明:渗透吸力对于黏土的等向压缩行为存在明显影响,主要体现在对初始弹性压缩线斜率、初始屈服应力的影响上。随着渗透吸力的增大,初始弹性压缩线斜率增大、初始屈服应力逐渐减小;而渗透吸力对弹塑段压缩线斜率和卸荷回弹线斜率影响不大。基于等向压缩试验结果,建立了盐溶液饱和黏土的本构模型,经过验证该模型能有效地模拟盐溶液饱和黏土的等向压缩特性。此外,该模型还可以模拟恒定等向压力下渗透吸力改变引起的试样变形。该等向压缩试验结果及所建立的模型为进一步分析及模拟化学-力学耦合行为提供了数据支持和理论基础。
In this paper, isotropic compression tests on clayey soil with pore water of different salt concentrations were carried out. Meanwhile, the testing results were used to analyze the effect of osmotic suction on compressibility. According to the experimental results, isotropic deformation characteristics were significantly influenced by osmotic suction. As osmotic suction increases, the slope of initial elastic compression line increases and stress decreases, while the effect of osmotic suction on the slopes of elasto-plastic compression lines and swelling lines can be neglected. Based upon the experimental results, a constitutive model considering in-pore salty solution influence for clayey soil is proposed under isotropic condition. Through the verification, the model is valid for simulation of isotropic compression behavior. Additionally, the proposed model could be adopted to simulate the response of saturated soil with salty solution to the change in osmotic suction. The experimental result is of vital importance to develop a constitutive model considering chemical-mechanical coupling.
In this paper, isotropic compression tests on clayey soil with pore water of different salt concentrations were carried out. Meanwhile, the testing results were used to analyze the effect of osmotic suction on compressibility. According to the experimental results, isotropic deformation characteristics were significantly influenced by osmotic suction. As osmotic suction increases, the slope of initial elastic compression line increases and stress decreases, while the effect of osmotic suction on the slopes of elasto-plastic compression lines and swelling lines can be neglected. Based upon the experimental results, a constitutive model considering in-pore salty solution influence for clayey soil is proposed under isotropic condition. Through the verification, the model is valid for simulation of isotropic compression behavior. Additionally, the proposed model could be adopted to simulate the response of saturated soil with salty solution to the change in osmotic suction. The experimental result is of vital importance to develop a constitutive model considering chemical-mechanical coupling.
引文
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[19]陈波,孙德安,吕海波.海相软土压缩特性的试验研究[J].岩土力学,2013,34(2):381-388.CHEN Bo,SUN De-an,LüHai-bo.Experimental study of compression behavior of marine soft clays[J].Rock and Soil Mechanics,2013,34(2):381-388.
[20]NAKASE A,KAMEI T,KUSAKABE O.Constitutive parameters estimated by plasticity index[J].Journal of Geotechnical Engineering,1988,114(7):844-858.
[21]TANG A M,CUI Y J,BAMEL N.Thermo-mechanical behaviour of a compacted swelling clay[J].Géotechnique,2008,58(1):45-54.
[22]NELSON J D,MILLER D J.Expansive soils:problems and practices in foundation and pavement engineering[M].New York:John Wiley&Sons,Inc.,1997.
[23]FREDLUND D G,RAHARDJO H.Soil mechanics for unsaturated soils[M].New York:John Wiley&Sons,Inc.,1993.
[24]MATA C,ROMERO E,LEDESMA A.Hydro-chemical effects on water retention in bentonite-sand mixtures[C]//Proceedings of the 3rd International Conference on Unsaturated soil.Lisse:Swets&Zeitlinger,2002:283-288.
[25]GLASSTONEl S.Textbook of physical chemistry[M].New Delhi:Macmillan Publisher Limited,1974.
[26]RAO S M,SHIVANANDA P.Role of osmotic suction in swelling of salt-amended clays[J].Canadian Geotechnical Journal,2005,42(1):307-315.
[27]LALOUI L,CEKEREVAC C.Thermo-plasticity of clays:an isotropic yield mechanism[J].Computers and Geotechnics,2003,30(8):649-660.
[28]HUECKEL T.Chemo-plasticity of clays subjected to stress and flow of a single contaminant[J].International Journal for Numerical and Analytical Methods in Geomechanics,1997,21(1):43-72.
[29]BOUKPETI N,CHARLIER R,HUECKEL T.Modelling contamination of clays[J].Elsevier Geo-Engineering Book Series,2004,2(4):523-528.
[2]唐晓武,应丰,寇乃羽,等.吸附离子对粉质黏土及改良土特性的影响[J].岩土力学,2010,31(8):2519-2524.TANG Xiao-wu,YING Feng,KOU Nai-yu,et al.Effects of cation adsorption on properties of silt clay and mixed dredged soil[J].Rock and Soil Mechanics,2010,31(8):2519-2524.
[3]SRIDHARAN A,VENKATAPPA RAO G.Shear strength behaviour of saturated clays and the role of the effective stress concept[J].Geotechnique,1979,29(2):177-193.
[4]DI MIAO C.Exposure of bentonite to salt solution:osmotic and mechanical effects[J].Geotechnique,1996,46(4):695-707.
[5]GAJO A,MAINES M.Mechanical effects of aqueous solutions of inorganic acids and bases on a natural active clay[J].Geotechnique,2007,57(8):687-699.
[6]ARASAN S,YETIMOGLU T.Effect of inorganic salt solutions on the consistency limits of two clays[J].Turkish Journal of Engineering and Environmental Sciences,2008,32(2):107-115.
[7]SRIDHARAN A.Engineering behavior of clays:influence of mineralogy[C]//Chemo-mechanical Coupling in Clays:From Nano-scale to Engineering Applications.Maratea:Swets and Zeitlinger,2001.
[8]PETROV R J,ROWE R K,QUIGLEY R M.Selected factors influencing GCL hydraulic conductivity[J].Journal of Geotechnical and Geoenvironmental Engineering,1997,123(8):683-695.
[9]GLEASON M H,DANIEL D E,EYKHOLT G R.Calcium and sodium bentonite for hydraulic containment applications[J].Journal of Geotechnical and Geoenvironmental Engineering,1997,123(5):438-445.
[10]CALVELLO M,LASCO M,VASSALLO R.Compressibility and residual shear strength of smectitic clays:influence of pore aqueous solutions and organic solvents[J].Italian Geotechnical Journal,2005,1:34-46.
[11]DI MIAO C,SANTOLI L,SCHIAVONE P.Volume change behavior of clays:the influence of mineral composition,pore fluid composition and stress state[J].Mechanics of materials,2004,36(5-6):435-451.
[12]WANG Y H,SIU W K.Structure characteristics and mechanical properties of kaolinite soils.I.surface charges and structural characterizations[J].Canadian Geotechnical Journal,2006,43(6):587-600.
[13]SRIDHARAN A,RAO A V.Shear strength behaviour of saturated clays and the role of the effective stress concept[J].Geotechnique,1979,29(2):177-193.
[14]SHARIATMADARI N,SALAMI M,FARD M K.Effect of inorganic salt solutions on some geotechnical properties of soil-bentonite mixtures as barriers[J].International Journal of Civil Engineering,2011,9(2):103-110.
[15]张彤炜,邓永锋,刘松玉,等.渗透吸力对重塑黏土的压缩和渗透特性影响的试验研究[J].岩土工程学报,2014,36(12):2260-2266.ZHANG Tong-wei,DENG Yong-feng,LIU Song-yu,et al.Experimental investigation of osmotic suction effect on hydro-mechanical behaviour of remolded clay[J].Chinese Journal of Geotechnical Engineering,2014,36(12):2260-2266.
[16]BARBOUR S L,FRDLUND D G.Mechanisms of osmotic flow and volume change in clay soils[J].Canadian Geotechnical Journal,1989,26(4):551-562.
[17]WITTEVEEN P J,FERRARI A,LALOUI L.An experimental and constitutive investigation on the chemo-mechanical behaviour of a clay[J].Geotechnique,2013,63(3):244-255.
[18]XU Y F,XIANG G S,JIANG H,et al.Role of osmotic suction in volume change of clays in salt solution[J].Applied Clay Science,2014,101:354-361.
[19]陈波,孙德安,吕海波.海相软土压缩特性的试验研究[J].岩土力学,2013,34(2):381-388.CHEN Bo,SUN De-an,LüHai-bo.Experimental study of compression behavior of marine soft clays[J].Rock and Soil Mechanics,2013,34(2):381-388.
[20]NAKASE A,KAMEI T,KUSAKABE O.Constitutive parameters estimated by plasticity index[J].Journal of Geotechnical Engineering,1988,114(7):844-858.
[21]TANG A M,CUI Y J,BAMEL N.Thermo-mechanical behaviour of a compacted swelling clay[J].Géotechnique,2008,58(1):45-54.
[22]NELSON J D,MILLER D J.Expansive soils:problems and practices in foundation and pavement engineering[M].New York:John Wiley&Sons,Inc.,1997.
[23]FREDLUND D G,RAHARDJO H.Soil mechanics for unsaturated soils[M].New York:John Wiley&Sons,Inc.,1993.
[24]MATA C,ROMERO E,LEDESMA A.Hydro-chemical effects on water retention in bentonite-sand mixtures[C]//Proceedings of the 3rd International Conference on Unsaturated soil.Lisse:Swets&Zeitlinger,2002:283-288.
[25]GLASSTONEl S.Textbook of physical chemistry[M].New Delhi:Macmillan Publisher Limited,1974.
[26]RAO S M,SHIVANANDA P.Role of osmotic suction in swelling of salt-amended clays[J].Canadian Geotechnical Journal,2005,42(1):307-315.
[27]LALOUI L,CEKEREVAC C.Thermo-plasticity of clays:an isotropic yield mechanism[J].Computers and Geotechnics,2003,30(8):649-660.
[28]HUECKEL T.Chemo-plasticity of clays subjected to stress and flow of a single contaminant[J].International Journal for Numerical and Analytical Methods in Geomechanics,1997,21(1):43-72.
[29]BOUKPETI N,CHARLIER R,HUECKEL T.Modelling contamination of clays[J].Elsevier Geo-Engineering Book Series,2004,2(4):523-528.