考虑黄土结构性和各向异性的修正剑桥模型
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摘要
天然原状黄土具有结构性和各向异性,如何在本构模型中合理反映两者的影响成为模型模拟效果优劣的关键。基于修正剑桥模型,在q?p平面内引入结构性参数pb反映天然黄土结构性,通过屈服面旋转的方法引入各向异性参数?反映天然黄土各向异性,模型硬化规律考虑了各向异性的影响,采用相关联流动法则,结合一致性条件推导了增量型应力-应变关系,建立了考虑黄土结构性和各向异性影响的修正剑桥模型。当不考虑结构性和各向异性时,模型退化为修正剑桥模型。模型共有8个参数,均可通过常规室内试验获得。选取天然原状黄土开展了三轴试验,试验结果与模型计算结果对比表明,考虑结构性和各向异性影响的修正剑桥模型模拟天然原状黄土的应力-应变特性效果优于修正剑桥模型。
As known, natural geotechnical materials always have the characteristics of structure and anisotropy. How to express their effects rationally in the constitutive model is the key point for evaluating the advantages and disadvantages of the constitutive model.On the basis of the modified Cam-clay model, a structural parameterpb was used to express structural characteristic of natural original soil in q ?p plain. An anisotropic parameter ? was used by rotating yield surface to express anisotropy effect. The anisotropic parameter also be used in the process of deducting the hardening rule. A modified Cam-clay model considering structural and anisotropic properties was established. Combined with the associated flow rule and consistency condition, the incremental stress-strain relationship from the constitutive model was derived. The model consisted of 8 parameters which can all be obtained by the conventional laboratory tests. At the last, the triaxial shear tests was carried out using natural original loess, the comparison of experimental results and model calculation shows that the modified Cam-clay model considering soil structure and anisotropy could simulate the mechanical characteristic of natural original loess correctly.
As known, natural geotechnical materials always have the characteristics of structure and anisotropy. How to express their effects rationally in the constitutive model is the key point for evaluating the advantages and disadvantages of the constitutive model.On the basis of the modified Cam-clay model, a structural parameterpb was used to express structural characteristic of natural original soil in q ?p plain. An anisotropic parameter ? was used by rotating yield surface to express anisotropy effect. The anisotropic parameter also be used in the process of deducting the hardening rule. A modified Cam-clay model considering structural and anisotropic properties was established. Combined with the associated flow rule and consistency condition, the incremental stress-strain relationship from the constitutive model was derived. The model consisted of 8 parameters which can all be obtained by the conventional laboratory tests. At the last, the triaxial shear tests was carried out using natural original loess, the comparison of experimental results and model calculation shows that the modified Cam-clay model considering soil structure and anisotropy could simulate the mechanical characteristic of natural original loess correctly.
引文
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[4]沈珠江.结构性黏土的堆砌体模型[J].岩土力学,2000,21(1):1-4.SHEN Zhu-jiang.A masonry model for structured clays[J].Rock and Soil Mechanics,2000,21(1):1-4.
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[7]邵生俊,周飞飞,龙吉勇.原状黄土结构性及其定量化参数研究[J].岩土工程学报,2004,26(4):531-536.SHAO Sheng-jun,ZHOU Fei-fei,LONG Ji-yong.Structural properties of loess and its quantitative parameter[J].Chinese Journal Geotechnical of Engineering,2004,26(4):531-536.
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[9]LIU M D,CARTER J P.A structured Cam clay model[J].Canadian Geotechnical Journal,2002,39(1):1313-1332.
[10]LIU M D,CARTER J P,DESAI C S.Modeling compression behavior of structured geomaterials[J].International Journal of Geomechanics,2003,3(2):191-204.
[11]ZHU E Y,YAO Y P.Structured UH model for clays[J].Transportation Geotechnics,2015(3):68-79.
[12]AHAD O.Disturbed state concept-based constitutive model for structured soils[J].International Journal of Geomechanics,2017,17(7):1-10.
[13]王立忠,沈恺伦.K0固结结构性软粘土的本构模型[J].岩土工程学报,2007,29(4):496-504.WANG Li-zhong,SHEN Kai-lun.A constitutive model of K0-consolided structured soft clays[J].Chinese Journal of Geotechnical Engineering,2007,29(4):496-504.
[14]WHEELER S J,NAATANEN A,KARSTUNEN M,et al.An anisotropic elastoplastic model for soft clays[J].Canadian Geotechnical Journal,2003,40:403-418.
[15]ZENTAR R,KARSTUNEN M,WHEELER S J.Influence of anisotropy and destructuration on undrained shearing of natural clays[C]//Proceedings of the 5th European Conference on Numerical Methods on Geotechnical Engineering.Paris:[s.n.],2002:21-26.
[16]ROSCOE K H,SCHOFIELD A N,WROTH C P.On the yielding of soil[J].Geotechnique,1958,8(l):22-53.
[17]ROSCOE K H,SCHOFIELD A N,THURAIRAJAH A.Yielding of clays in states wetter than critical[J].Geotechnique,1963,13(3):211-240.
[18]李顺群,张建伟,夏锦红.原状土的剑桥模型和修正剑桥模型[J].岩土力学,2015,36(增刊2):215-220.LI Shun-qun,ZHANG Jian-wei,XIA Jin-hong.An improvement on Cam clay model and modified Cam clay model for intact soil[J].Rock and Soil Mechanics,2015,36(Suppl.2):215-220.
[19]COLLINS I F,HILDER T.A theoretical framework for constructing elastic/plastic constitutive models of triaxial test[J].International Journal for Numerical and Analytical Methods in Geomechanics,2002,26:1313-1347.
[20]YANG C,CUI Y J,PEREIRA J M,et al.A constitutive model for unsaturated cemented soils under cyclic loading[J].Computers and Geotechnics,2008,35(1):853-859
[21]石博溢,倪万魁,王衍汇.重塑黄土压缩变形的预测模型研究[J].岩土力学,2016,37(7):1963-1968.SHI Bo-yi,NI Wan-kui,WANG Yan-hui.A model for calculating the compressive deformation of remolded loess[J].Rock and Soil Mechanics,2016,37(7):1963-1968.
[22]交通部公路科学研究院.JTG E40-2007公路土工试验规程[S].北京:交通部公路科学研究院,2007.Research Institute of Highway Ministry of Transport.JTGE40-2007 Test methods of soils for highway engineering[S].Beijing:Research Institute of Highway Ministry of Transport,2007.
[23]殷杰.结构性软黏土的修正剑桥模型[J].工程力学,2013,30(1):190-197.YIN Jie.A modified Cam-clay model for structured soft clays[J].Engineering Mechanics,2013,30(1):190-197.
[24]邓国华,邵生俊,佘芳涛.结构性黄土的修正剑桥模型[J].岩土工程学报,2012,34(5):834-840.DENG Guo-hua,SHAO Sheng-jun,SHE Fang-tao.Modified Cam-clay model of structured loess[J].Chinese Journal of Geotechnical Engineering,2012,34(5):834-840.
[2]沈珠江.土体结构性的数学模型―21世纪土力学的核心问题[J].岩土工程学报,1996,18(1):95-97.SHEN Zhu-jiang.Mathematical modeling of soil structure―the key problem of soil mechanics in 21st century[J].Chinese Journal of Geotechnical Engineering,1996,18(1):95-97.
[3]沈珠江.结构性黏土的弹塑性损伤模型[J].岩土工程学报,1993,15(3):1-6.SHEN Zhu-jiang.An elasto-plastic damage model for cemented clays[J].Chinese Journal of Geotechnical Engineering,1993,15(3):1-6.
[4]沈珠江.结构性黏土的堆砌体模型[J].岩土力学,2000,21(1):1-4.SHEN Zhu-jiang.A masonry model for structured clays[J].Rock and Soil Mechanics,2000,21(1):1-4.
[5]谢定义,齐吉琳.土结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656.XIE Ding-yi,QI Ji-lin.Soil structure characteristics and new approach in research on its quantitative parameter[J].Chinese Journal of Geotechnical Engineering,1999,21(6):651-656.
[6]谢定义,齐吉琳,张振中.考虑土结构性的本构关系[J].土木工程学报,2000,33(4):35-41.XIE Ding-yi,QI Ji-lin,ZHANG Zhen-zhong.Aconstitutive laws considering soil structural properties[J].China Civil Engineering Journal,2000,33(4):35-41.
[7]邵生俊,周飞飞,龙吉勇.原状黄土结构性及其定量化参数研究[J].岩土工程学报,2004,26(4):531-536.SHAO Sheng-jun,ZHOU Fei-fei,LONG Ji-yong.Structural properties of loess and its quantitative parameter[J].Chinese Journal Geotechnical of Engineering,2004,26(4):531-536.
[8]邵生俊,龙吉勇,于清高,等.湿陷性黄土的结构性参数本构模型[J].水利学报,2006,37(11):1315-1322.SHAO Sheng-jun,LONG Ji-yong,YU Qing-gao,et al.Aconstitutive model of collapsible loess with structure parameter[J].Journal of Hydraulic Engineering,2006,37(11):1315-1322.
[9]LIU M D,CARTER J P.A structured Cam clay model[J].Canadian Geotechnical Journal,2002,39(1):1313-1332.
[10]LIU M D,CARTER J P,DESAI C S.Modeling compression behavior of structured geomaterials[J].International Journal of Geomechanics,2003,3(2):191-204.
[11]ZHU E Y,YAO Y P.Structured UH model for clays[J].Transportation Geotechnics,2015(3):68-79.
[12]AHAD O.Disturbed state concept-based constitutive model for structured soils[J].International Journal of Geomechanics,2017,17(7):1-10.
[13]王立忠,沈恺伦.K0固结结构性软粘土的本构模型[J].岩土工程学报,2007,29(4):496-504.WANG Li-zhong,SHEN Kai-lun.A constitutive model of K0-consolided structured soft clays[J].Chinese Journal of Geotechnical Engineering,2007,29(4):496-504.
[14]WHEELER S J,NAATANEN A,KARSTUNEN M,et al.An anisotropic elastoplastic model for soft clays[J].Canadian Geotechnical Journal,2003,40:403-418.
[15]ZENTAR R,KARSTUNEN M,WHEELER S J.Influence of anisotropy and destructuration on undrained shearing of natural clays[C]//Proceedings of the 5th European Conference on Numerical Methods on Geotechnical Engineering.Paris:[s.n.],2002:21-26.
[16]ROSCOE K H,SCHOFIELD A N,WROTH C P.On the yielding of soil[J].Geotechnique,1958,8(l):22-53.
[17]ROSCOE K H,SCHOFIELD A N,THURAIRAJAH A.Yielding of clays in states wetter than critical[J].Geotechnique,1963,13(3):211-240.
[18]李顺群,张建伟,夏锦红.原状土的剑桥模型和修正剑桥模型[J].岩土力学,2015,36(增刊2):215-220.LI Shun-qun,ZHANG Jian-wei,XIA Jin-hong.An improvement on Cam clay model and modified Cam clay model for intact soil[J].Rock and Soil Mechanics,2015,36(Suppl.2):215-220.
[19]COLLINS I F,HILDER T.A theoretical framework for constructing elastic/plastic constitutive models of triaxial test[J].International Journal for Numerical and Analytical Methods in Geomechanics,2002,26:1313-1347.
[20]YANG C,CUI Y J,PEREIRA J M,et al.A constitutive model for unsaturated cemented soils under cyclic loading[J].Computers and Geotechnics,2008,35(1):853-859
[21]石博溢,倪万魁,王衍汇.重塑黄土压缩变形的预测模型研究[J].岩土力学,2016,37(7):1963-1968.SHI Bo-yi,NI Wan-kui,WANG Yan-hui.A model for calculating the compressive deformation of remolded loess[J].Rock and Soil Mechanics,2016,37(7):1963-1968.
[22]交通部公路科学研究院.JTG E40-2007公路土工试验规程[S].北京:交通部公路科学研究院,2007.Research Institute of Highway Ministry of Transport.JTGE40-2007 Test methods of soils for highway engineering[S].Beijing:Research Institute of Highway Ministry of Transport,2007.
[23]殷杰.结构性软黏土的修正剑桥模型[J].工程力学,2013,30(1):190-197.YIN Jie.A modified Cam-clay model for structured soft clays[J].Engineering Mechanics,2013,30(1):190-197.
[24]邓国华,邵生俊,佘芳涛.结构性黄土的修正剑桥模型[J].岩土工程学报,2012,34(5):834-840.DENG Guo-hua,SHAO Sheng-jun,SHE Fang-tao.Modified Cam-clay model of structured loess[J].Chinese Journal of Geotechnical Engineering,2012,34(5):834-840.