为了研究结构性软黏土一维压缩变形特性的影响,在软黏土一维压缩结构破坏特征的基础上,揭示了压缩指数随孔隙比的变化规律,提出了土体结构渐进破坏的数学描述模式;基于上述描述模式,首先推导了一维压缩曲线的数学表达式,分析了结构效应参数对压缩曲线性状的影响规律;然后利用10种典型结构性软黏土的一维压缩试验结果对数学描述模式进行了验证,并以Mexico City clay为例,将描述模式和其他6种常用描述模式的模拟效果进了对比分析;最后分析了软黏土结构效应参数随(w-wP)的变化规律,通过线性回归得出了结构效应参数的经验关系式。研究结果表明提出的描述模式能较准确地描述一维条件下结构性软黏土的压缩变形的结构破坏特征。成果为建立结构性软黏土的本构模型提供了一定的理论基础,也为进一步研究结构性软黏土的变形特性提出了新的思路。
Abstract
In order to explore the effect of structure on one-dimensional compression deformation of soft clays, we described the characteristics of structural failure under one-dimensional compression firstly. On this basis, the relationship between compression index and void ratio was revealed and a new mode that describes the progressive destructuration during the 1D compression was proposed. Secondly, the formula of the virgin compression curve of structured soft clays is deduced based on the above proposed descriptive mode and the effects of structural parameters on the virgin compression curves are analyzed. Thirdly, the experimental data of 10 representative structured clays from literatures together with the results of conventional oedometer tests on Ningbo clay are used to verify the proposed descriptive mode’s validity. Furthermore, a comparative analysis on the simulated results of 1D compression curves for Mexico City clays is made between the proposed descriptive mode and other 6 common descriptive modes. Finally, the variation regularity of structural parameters with the difference between nature water content and plastic limit is discussed and then the empirical formulas of structural parameters are established by the linear regression method. The results show that the proposed descriptive mode characterizes the compression destructural behavior of structured soft clays under 1D loading condition accurately. This research provides theoretical basis for establishing constitutive models of natural structured soft clays, and also offers a new idea for further study on compression deformation behavior.
关键词
软黏土 /
土体结构性 /
结构破坏 /
压缩特性 /
数学描述 /
原始压缩曲线 /
结构效应参数
Key words
soft clay /
structural property of soil /
destructuration /
compression behavior /
mathematical description /
virgin compression curves /
structural parameter
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参考文献
[1] BAUDET B, STALLEBRASS S. A Constitutive Model for Structured Clays[J]. Géotechnique, 2004, 54(4): 269-278.
[2] LEROUEIL S, VAUGHAN P R. The General and Congruent Effects of Structure in Natural Soils and Weak Rocks[J]. Geotechnique, 1990, 40(3): 467-488.
[3] 罗爱忠,邵生俊,陈昌禄,等. 基于综合结构势的结构性黄土双硬化参数模型[J]. 长江科学院院报, 2013,30(9): 59-63.
[4] 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.
[5] 沈珠江. 结构性粘土的弹塑性损伤模型[J]. 岩土工程学报, 1993,15(3): 21-28.
[6] 刘恩龙,沈珠江. 结构性土的二元介质模型[J]. 水利学报, 2005,36(4): 391-395.
[7] DESAI C S. Mechanics of Materials and Interfaces: The Disturbed State Concept[M]. Boca Raton: CRC Press, 2001.
[8] LIU M D, CARTER J P. Modelling the Destructuring of Soils during Virgin Compression[J]. Geotechnique, 2000, 50(4): 479-483.
[9] YIN Z, KARSTUNEN M, CHANG C S, et al. Modeling Time-dependent Behavior of Soft Sensitive Clay[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2011, 137(11): 1103-1113.
[10]BUTTERFIELD R. A Natural Compression Law for Soils (An Advance on e-logp')[J]. Géotechnique, 1979, 29(4):469-480.
[11]CHAI J, MIURA N, ZHU H, et al. Compression and Consolidation Characteristics of Structured Natural Clay[J]. Canadian Geotechnical Journal, 2004, 41(6): 1250-1258.
[12]LOW H, PHOON K, TAN T, et al. Effect of Soil Microstructure on the Compressibility of Natural Singapore Marine Clay[J]. Canadian Geotechnical Journal, 2008, 45(2): 161-176.
[13]JUNG Y, FINNO R J, CHO W. Stress-strain Responses of Reconstituted and Natural Compressible Chicago Glacial clay[J].Engineering Geology,2012,129(1): 9-19.
[14]BJERRUM L. Engineering Geology of Norwegian Normally-consolidated Marine Clays as Related to Settlements of Buildings[J]. Geotechnique, 1967, 17(2): 83-118.
[15]JIA R. Consolidation Behavior of Ariake Clay under Constant Rate of Strain[D]. Saga, Japan: Saga University, 2010.
[16]LEROUEIL S, KABBAJ M, TAVENAS F. Study of the Validity of a σ′v-εv-ε·vModel in In situ Conditions[J]. Soils and Foundations, 1988, 28(3): 13-25.
[17]LEROUEIL S, KABBAJ M, TAVENAS F, et al. Stress-strain-strain Rate Relation for the Compressibility of Sensitive Natural Clays[J]. Geotechnique, 1985, 35(2): 159-180.
[18]SMITH P R, JARDINE R J, HIGHT D W. The Yielding of Bothkennar Clay[J]. Géotechnique, 1992, 42(2): 257-274.
[19]LIU M D, CARTER J P. Virgin Compression of Structured Soils[J]. Géotechnique, 1999, 49(1): 43-57.
[20]ISLAM M K, CARTER J P, SIDDIQUEE M, et al. A Method for Derivation of Compression Equation and Value of Degradation Exponent for Structured Soils[J]. Geotechnical and Geological Engineering, 2013, 31(5): 1587-1601.
[21]MESRI G, ROKHSAR A, BOHOR B F. Composition and Compressibility of Typical Samples of Mexico City Clay[J]. Geotechnique, 1975, 25(3): 527-554.
[22]PERRET D, LOCAT J, LEROUEIL S. Strength Development with Burial in Fine-grained Sediments from the Saguenay Fjord, Quebec[J]. Canadian Geotechnical Journal, 1995, 32(2): 247-262.
[23]TANAKA H, LOCAT J, SHIBUYA S, et al. Characterization of Singapore, Bangkok, and Ariake Clays[J]. Canadian Geotechnical Journal, 2001, 38(2): 378-400.
[24]曾玲玲,洪振舜,刘松玉,等. 天然沉积结构性土的次固结变形预测方法[J]. 岩土力学, 2011,32(10): 3136-3142.
[25]DEN HAAN E J. The Formulation of Virgin Compression of Soils[J]. Géotechnique, 1992, 42(3): 465-483.
基金
国家自然科学基金重大研究计划集成项目(91215301);国家重点基础研究发展计划973项目(2015CB057905);中国科学院重点部署项目、百人计划项目(NKZZDEWTZ12)
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