考虑结构性影响的原状软黏土应力–应变特性真三轴试验研究
|
摘要
通过对营口原状软黏土和饱和重塑软黏土的真三轴试验,研究围压和中主应力系数对软黏土强度的影响。基于综合结构势理论,提出真三维应力条件下软黏土的应力比结构性参数,建立引入结构性参数的原状软黏土偏应力–广义剪应变关系式。研究结果表明:当固结围压<先期固结压力时,原状软黏土偏应力–广义剪应变曲线形态表现为应变软化,体应变表现为剪缩特性;当固结围压>先期固结压力时,其曲线形态表现为应变硬化,体积应变表现为剪胀特性;饱和重塑软黏土的偏应力–应变关系曲线则不受先期固结压力的影响,均表现为应变硬化型。软黏土强度都随着固结围压和中主应力系数的增大而增大。应力比结构性参数m_η随广义剪应变、固结围压和中主应力系数的增大而降低,其与广义剪应变呈显著的对数关系。将拟合得到的应力比结构性参数m_η引入到原状软黏土的q-ε_s曲线中,得到q/m_η-ε_s关系曲线,进而建立引入结构性参数的原状软黏土偏应力–广义剪应变关系式,其与试验结果具有较好的一致性,从而使原状软黏土q-ε_s曲线得到合理描述。
The true triaxial tests to the undisturbed and the saturated remould soft clay from the city of Yingkou were carried out to study the effect of confining pressure and principal stress on the strength of soft clay. The stress ratio of soft clay under the three-dimensional stress conditions is presented according to the comprehensive structure potential theory and the relationship between the deviatoric stress and the generalized shear strain of the undisturbed soft clay with structural parameters is established. The curve of the deviatoric stress(q) vs the generalized shear strain(ε_s) of undisturbed soft clay is related to the pre-consolidation pressures. It is strain softening when the confining pressures are smaller than the pre-consolidation pressures and the volumetric strain appears shear shrinkage. It is strain hardening when the confining pressures are larger than the pre-consolidation pressures and the volumetric strain appears shear dilation. The type of curves of q vs.ε_s of the disturbed saturated soft clay is not affected by the structural yield stress and is basically the strain hardening one. The strengths of undisturbed soft clay and saturated soft clay are increased with the increasing of the confining pressure and coefficient of the principal stress. But the structural parameters of stress ratio decreased with the increasing of the shear strain,confining pressure and coefficient of the principal stress. The structural parameters of stress ratio varies logarithmically with the generalized shear strain. The structural parameters of stress ratio was introduced into the q-ε_s curves of undisturbed soft clay and the q/m_η-ε_s curves were thus obtained. The relationship between the deviatoric stress and the generalized shear strain for undisturbed soft clay was established and it has a good agreement with the experimental results.
The true triaxial tests to the undisturbed and the saturated remould soft clay from the city of Yingkou were carried out to study the effect of confining pressure and principal stress on the strength of soft clay. The stress ratio of soft clay under the three-dimensional stress conditions is presented according to the comprehensive structure potential theory and the relationship between the deviatoric stress and the generalized shear strain of the undisturbed soft clay with structural parameters is established. The curve of the deviatoric stress(q) vs the generalized shear strain(ε_s) of undisturbed soft clay is related to the pre-consolidation pressures. It is strain softening when the confining pressures are smaller than the pre-consolidation pressures and the volumetric strain appears shear shrinkage. It is strain hardening when the confining pressures are larger than the pre-consolidation pressures and the volumetric strain appears shear dilation. The type of curves of q vs.ε_s of the disturbed saturated soft clay is not affected by the structural yield stress and is basically the strain hardening one. The strengths of undisturbed soft clay and saturated soft clay are increased with the increasing of the confining pressure and coefficient of the principal stress. But the structural parameters of stress ratio decreased with the increasing of the shear strain,confining pressure and coefficient of the principal stress. The structural parameters of stress ratio varies logarithmically with the generalized shear strain. The structural parameters of stress ratio was introduced into the q-ε_s curves of undisturbed soft clay and the q/m_η-ε_s curves were thus obtained. The relationship between the deviatoric stress and the generalized shear strain for undisturbed soft clay was established and it has a good agreement with the experimental results.
引文
[1]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 Zhujiang.The mathematical model of soil structure—the core issue of soil mechanics in the 21st century[J].Chinese Journal of Geotechnical Engineering,1996,18(1):95–97.(in Chinese))
[2]DESAI C S.Mechanics of materials and interfaces-the disturbed state concept[M].[s.n.]:CRC Press,2001:41–52.
[3]KOKUSHO T,YOSHIDA Y,ESAHI Y.Dynamic properties of soft clays for wide strain range[J].Soils and Foundations,1982,(4):1–18.
[4]钟祖良,王睢,刘新荣.基于综合结构势概念的结构性原状黄土屈服准则[J].岩土力学,2015,36(11):3 041–3 046.(ZHONG Zuliang,WANG Sui,LIU Xinrong.Yield criterion of intact structural loess based on integrated structural potential concept[J].Rock and Soil Mechanics,2015,36(11):3 041–3 046.(in Chinese))
[5]骆亚生,谢定义,邵生俊,等.复杂应力条件下的土结构性参数[J].岩石力学与工程学报,2004,23(24):4 248–4 251.(LUO Yasheng,XIE Dingyi,SHAO Shengjun,et al.Structural parameter of soil under complex stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(24):4 248–4 251.(in Chinese))
[6]骆亚生.非饱和黄土在动、静复杂应力条件下的结构变化特性及结构性本构关系研究[博士学位论文][D].西安:西安理工大学,2003.(LUO Yasheng.Variation characteristics of soil structural and structural constitutive relation of unsaturated loess under static and dynamic complex stress conditions[Ph.D.Thesis][D].Xi?an:Xi?an University of Technology,2003.(in Chinese))
[7]骆亚生.非饱和黄土在动、静复杂应力条件下的结构变化特性及结构性本构关系研究[J].岩石力学与工程学报,2004,23(11):1 959.(LUO Yasheng.Variation characteristics of soil structural and structural constitutive relation of unsaturated loess under static and dynamic complex stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(11):1 959.(in Chinese))
[8]张向东,刘家顺,张哲诚.动荷载作用下阜新风积土结构性参数试验研究[J].工业建筑,2013,43(8):83–89.(ZHANG Xiangdon,LIU Jiashun,ZHANG Zhecheng.Experimental study on structural parameters of Fuxin aeolian soil under dynamic loads[J].Industrial Construction,2013,43(8):83–89.(in Chinese))
[9]CHOI C,ARDUINO P,HARNEY M D.Development of a true triaxial apparatus for sands and gravels[J].Geotechnical Testing Journal,2007,31(1):1–13.
[10]邓国华.真三轴条件下黄土的结构性参数及结构性本构关系研究[博士学位论文][D].西安:西安理工大学,2009.(DENG Guohua.Research on Structure Parameter of Loess and Structure Constitutive Relations under True Tri-axial Condition[Ph.D.Thesis][D].Xi?an:Xi'an University of Technology,2009.(in Chinese))
[11]邓国华,邵生俊,陈昌禄,等.一个可考虑球应力和剪应力共同作用的结构性参数[J].岩土力学,2012,33(8):2 310–2 314.(DENG Guohua,SHAO Shengjun,CHEN Changlu,et al.A structural parameter reflecting coupling action between shear stress and spherical stress[J].Rock and Soil Mechanics,2012,33(8):2 310–2 314.(in Chinese))
[12]邓国华,邵生俊.基于真三轴试验的黄土结构性变化规律研究[J].岩土力学,2013,34(3):679–684.(DENG Guohua,SHAO Shengjun.Research on change structural characteristics of loess based on true triaxial tests[J].Rock and Soil Mechanics,2013,34(3):679–684.(in Chinese))
[13]邓国华,邵生俊,高虎艳.土的综合结构势及结构性参数研究进展[J].岩土力学,2009,30(增2):178–184.(DENG Guohua,SHAO Shengjun,GAO Huyan.Advances in comprehensive structural potential and structural parameters of soils[J].Rock and Soil Mechanics,2009,30(Supp.2):178–184.(in Chinese))
[14]田堪良,马俊,李永红.黄土结构性定量化参数的探讨[J].岩石力学与工程学报,2011,30(增1):3 179–3 184.(TIAN Kanliang,MA Jun,LI Yonghong.Discussion on quantitative parameters of loess structural[J].Chinese Journal of Rock mechanics and Engineering,2011,30(Supp.1):3 179–3 184.(in Chinese))
[15]中华人民共和国行业标准编写组.TB10102—2010铁路土工试验规程[S].北京:中国铁道出版社,2011.(The Professional Standards Compilation Group of People?s Republic of China.TB10102—2010Railway geotechnical test procedures[S].Beijing:China Railway Publishing House,2011.(in Chinese)
[2]DESAI C S.Mechanics of materials and interfaces-the disturbed state concept[M].[s.n.]:CRC Press,2001:41–52.
[3]KOKUSHO T,YOSHIDA Y,ESAHI Y.Dynamic properties of soft clays for wide strain range[J].Soils and Foundations,1982,(4):1–18.
[4]钟祖良,王睢,刘新荣.基于综合结构势概念的结构性原状黄土屈服准则[J].岩土力学,2015,36(11):3 041–3 046.(ZHONG Zuliang,WANG Sui,LIU Xinrong.Yield criterion of intact structural loess based on integrated structural potential concept[J].Rock and Soil Mechanics,2015,36(11):3 041–3 046.(in Chinese))
[5]骆亚生,谢定义,邵生俊,等.复杂应力条件下的土结构性参数[J].岩石力学与工程学报,2004,23(24):4 248–4 251.(LUO Yasheng,XIE Dingyi,SHAO Shengjun,et al.Structural parameter of soil under complex stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(24):4 248–4 251.(in Chinese))
[6]骆亚生.非饱和黄土在动、静复杂应力条件下的结构变化特性及结构性本构关系研究[博士学位论文][D].西安:西安理工大学,2003.(LUO Yasheng.Variation characteristics of soil structural and structural constitutive relation of unsaturated loess under static and dynamic complex stress conditions[Ph.D.Thesis][D].Xi?an:Xi?an University of Technology,2003.(in Chinese))
[7]骆亚生.非饱和黄土在动、静复杂应力条件下的结构变化特性及结构性本构关系研究[J].岩石力学与工程学报,2004,23(11):1 959.(LUO Yasheng.Variation characteristics of soil structural and structural constitutive relation of unsaturated loess under static and dynamic complex stress conditions[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(11):1 959.(in Chinese))
[8]张向东,刘家顺,张哲诚.动荷载作用下阜新风积土结构性参数试验研究[J].工业建筑,2013,43(8):83–89.(ZHANG Xiangdon,LIU Jiashun,ZHANG Zhecheng.Experimental study on structural parameters of Fuxin aeolian soil under dynamic loads[J].Industrial Construction,2013,43(8):83–89.(in Chinese))
[9]CHOI C,ARDUINO P,HARNEY M D.Development of a true triaxial apparatus for sands and gravels[J].Geotechnical Testing Journal,2007,31(1):1–13.
[10]邓国华.真三轴条件下黄土的结构性参数及结构性本构关系研究[博士学位论文][D].西安:西安理工大学,2009.(DENG Guohua.Research on Structure Parameter of Loess and Structure Constitutive Relations under True Tri-axial Condition[Ph.D.Thesis][D].Xi?an:Xi'an University of Technology,2009.(in Chinese))
[11]邓国华,邵生俊,陈昌禄,等.一个可考虑球应力和剪应力共同作用的结构性参数[J].岩土力学,2012,33(8):2 310–2 314.(DENG Guohua,SHAO Shengjun,CHEN Changlu,et al.A structural parameter reflecting coupling action between shear stress and spherical stress[J].Rock and Soil Mechanics,2012,33(8):2 310–2 314.(in Chinese))
[12]邓国华,邵生俊.基于真三轴试验的黄土结构性变化规律研究[J].岩土力学,2013,34(3):679–684.(DENG Guohua,SHAO Shengjun.Research on change structural characteristics of loess based on true triaxial tests[J].Rock and Soil Mechanics,2013,34(3):679–684.(in Chinese))
[13]邓国华,邵生俊,高虎艳.土的综合结构势及结构性参数研究进展[J].岩土力学,2009,30(增2):178–184.(DENG Guohua,SHAO Shengjun,GAO Huyan.Advances in comprehensive structural potential and structural parameters of soils[J].Rock and Soil Mechanics,2009,30(Supp.2):178–184.(in Chinese))
[14]田堪良,马俊,李永红.黄土结构性定量化参数的探讨[J].岩石力学与工程学报,2011,30(增1):3 179–3 184.(TIAN Kanliang,MA Jun,LI Yonghong.Discussion on quantitative parameters of loess structural[J].Chinese Journal of Rock mechanics and Engineering,2011,30(Supp.1):3 179–3 184.(in Chinese))
[15]中华人民共和国行业标准编写组.TB10102—2010铁路土工试验规程[S].北京:中国铁道出版社,2011.(The Professional Standards Compilation Group of People?s Republic of China.TB10102—2010Railway geotechnical test procedures[S].Beijing:China Railway Publishing House,2011.(in Chinese)