基于起始水力坡降的软土一维大变形固结分析

doi:10.13722/j.cnki.jrme.2014.0330

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摘要深厚软黏土的大变形特性以及土中渗流存在的起始水力坡降已分别为人们所认识，但能考虑起始水力坡降的深厚软土大变形固结理论报道甚少。假定土的体积压缩系数保持不变，渗透系数与孔隙比为平方关系，在拉格朗日坐标系中建立以超静孔隙水压力为变量考虑起始水力坡降的软土大变形固结问题的控制方程及求解条件。利用有限差分法解决了由起始水力坡降所引起的动边界问题，将很小起始水力坡降下(10－5)的差分解与达西渗流定律下解析解对比，验证了差分数值计算结果的可靠性，从而为解决移动边界问题提供了一种有效方法。最后着重分析了量纲一变量R对固结性状的影响及在大、小应变不同几何假定下固结性状的区别，结果表明：R值的大小会影响渗流前锋的最终位置及移动速度、超静孔压的消散速率。R值越大，渗流前锋的移动速度越慢，土中超静孔压消散越慢，残留于土中而不能消散的超静孔压越大，进而导致土体发生的最终沉降量就越小。大变形几何假定下土中超静孔压的消散速率要比小变形几何假定下快，且固结完成时残留于土中不能消散的超静孔压值要比小变形几何假定下小，故计算得到的地基最终沉降量要比小变形几何假定下的计算值大。

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关键词 ：土力学, 起始水力坡降, 大变形固结, 有限差分法, 一维固结, 软土

Abstract：Threshold gradients and large deformation of thick soft soil may have been realized by researchers. However，the theory of large strain consolidation of soft clay with threshold gradient has rarely been reported. Supposing the constant coefficient of volume compressibility and the square relationship between coefficient of permeability and void ratio，the governing equation and solution conditions of large strain consolidation of soft clay with threshold gradient are developed in Lagrangian coordinates，in which excess pore water pressure serves as a variable. Finite difference method is adopted to obtain the solution for the problem of moving boundary which is induced by threshold gradients，and the reliability of numerical results is verified by comparing the numerical solutions under tiny threshold gradient(10－5) with analytical solutions in case of Darcy?s flow law. Thus，an effective method is provided to solve the problem of moving boundary. Finally，the influence of dimensionless variable R on consolidation behavior and the difference of consolidation behavior between large-strain and small-strain assumptions are analyzed，and the results show that the value of dimensionless variable R influences the final flow front location，the moving rate of flow front location and the dissipation rate of excess pore water pressure. The larger the value of R is，the slower the moving rate of flow front location is，and the slower the dissipation rate of excess pore water pressure is. The larger the value of R is，the larger the residual excess pore water pressure is, and the less the final settlement of soil layer is. The dissipation rate of excess pore water pressure with large-strain assumption is faster than that with small-strain assumption；furthermore，the residual excess pore water pressure with large-strain assumption is less than that with small-strain assumption. This consolidation behavior results in that the final settlement of foundation with large-strain assumption is larger than that with small-strain assumption.

Key words： soil mechanics threshold gradient large strain consolidation finite difference method one-dimensional consolidation soft soil

引用本文:

李传勋1，徐超1，谢康和2. 基于起始水力坡降的软土一维大变形固结分析[J]. 岩石力学与工程学报, 2015, 34(s1): 3518-3524.
LI Chuanxun1，XU Chao1，XIE Kanghe2. ANALYSIS OF ONE-DIMENSIONAL LARGE STRAIN CONSOLIDATION OF SOFT CLAY WITH THRESHOLD GRADIENT. , 2015, 34(s1): 3518-3524.

链接本文:

http://www.rockmech.org/CN/10.13722/j.cnki.jrme.2014.0330 或 http://www.rockmech.org/CN/Y2015/V34/Is1/3518

[2]	MILLER R J，LOW P E. Threshold gradient for water flow in clay systems[J]. Soil Science Society of American Journal，1963，27(6)：605-609. " target="_blank">
[3]	PASCAL F，PASCAL H，MURRAY D W. Consolidation with threshold gradients[J]. International Journal for Numerical and Analytical Methods in Geomechanics，1981，5(3)：247-261. " target="_blank">
[5]	刘忠玉，张天航，马崇武. 起始水力梯度对饱和黏土一维固结的影响[J]. 岩土力学，2007，28(3)：467-470.(LIU Zhongyu，ZHANG Tianhang，MA Chongwu. Effect of initial hydraulic gradient on one-dimensional consolidation of saturated clays[J]. Rock and Soil Mechanics，2007，28(3)：467-470.(in Chinese))
[7]	王坤，谢康和，刘兴旺，等. 初始孔压非均布考虑起始比降的一维固结解[J]. 岩土工程学报，2011，33(9)：1 419-1 424.(WANG Kun，XIE Kanghe，LIU Xingwang，et al. Solution for one-dimensional consolidation with threshold gradient subjected to non-uniformly distributed initial pore water pressure[J]. Chinese Journal of Geotechnical Engineering，2011，33(9)：1 419-1 424.(in Chinese))
[8]	王坤，谢康和，李传勋，等. 特殊条件下考虑起始比降的双层地基一维固结解析解[J]. 工程力学，2011，28(11)：78-82.(WANG Kun，XIE Kanghe，LI Chuanxun，et al. Analytical solution for one dimensional consolidation of double-layered ground with threshold gradient under special condition[J]. Engineering Mechanics，2011，28(11)：78-82.(in Chinese))
[11]	GIBSON R E，SCHIFFMAN R L，CARGILL K W. The theory of one-dimensional consolidation of saturated clays：II. finite non-linear consolidation of thick homogeneous layers[J]. Canadian Geotechnical Journal，1981，18(2)：280-293. " target="_blank">
[14]	谢康和，郑辉，LEO C J. 变荷载下饱和软黏土一维大应变固结解析理论[J]. 水利学报，2003，34(10)：6-13.(XIE Kanghe，ZHENG Hui，LEO C J. Analytical solution for 1-D large strain consolidation of saturated soft clay under time-depending loading[J]. Journal of Hydraulic Engineering，2003，34(10)：6-13.(in Chinese))
[16]	李传勋，谢康和，胡安峰，等. 基于指数形式渗流定律考虑初始有效应力非均匀分布的软土一维非线性固结分析[J]. 岩石力学与工程学报，2012，31(增1)：3 270-3 277.(LI Chuanxun，XIE Kanghe，HU Anfeng，et al. Analysis of one-dimensional nonlinear consolidation of soft considering exponential flow law and non-uniform distribution of initial effective stress[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(Supp.1)：3 270-3 277.(in Chinese)) " target="_blank">
[1]	HANSBO S. Consolidation of clay with special reference to influence of vertical drains[C]// Proceedings of Swedish Geotechnical Institute. Stockholm：Swedish Geotechnical Institute，1960：45-50. " target="_blank">
[12]	李冰河，应宏伟，谢康和，等. 考虑土体自重的一维大应变固结分析[J]. 土木工程学报，2000，33(3)：54-59.(LI Binghe，YING Hongwei，XIE Kanghe，et al. Analysis of 1D large-strain consolidation considering the self-weight of soils[J]. China Civil Engineering Journal，2000，33(3)：54-59.(in Chinese)) " target="_blank">
[6]	XIE K H，WANG K，WANG Y L，et al. Analytical solution for one-dimensional consolidation of clayey soils with a threshold gradient[J]. Computers and Geotechnics，2010，37(4)：487-493.
[9]	王坤. 考虑起始比降的软土地基一维固结理论研究[博士学位论文][D]. 杭州：浙江大学，2011.(WANG Kun. Studies on one-dimensional consolidation theory for soft soils with threshold gradient[Ph. D. Thesis][D]. Hangzhou：Zhejiang university，2011.(in Chinese)) " target="_blank">
[4]	刘慈群. 有起始比降固结问题的近似解[J]. 岩土工程学报，1982，4(3)：107-109.(LIU Ciqun. Approximate solution for one-dimensional consolidation with threshold gradient[J]. Chinese Journal of Geotechnical Engineering，1982，4(3)：107-109.(in Chinese))
[10]	GIBSON R E，ENGLAND G L，HUSSEY M J L. The theory of one-dimensional consolidation of saturated clays：I. finite non-linear consolidation of thin homogeneous layers[J]. Geotechnique，1967，17(2)：261-273. " target="_blank">
[13]	XIE K H，LEO C J. Analytical solutions of one-dimensional large strain consolidation of saturated and homogeneous clays[J]. Computers and Geotechnics，2004，31(4)：301-314.
[15]	黄杰卿，谢新宇，王文军，等. 考虑起始比降的饱和土体一维复杂非线性固结研究[J]. 岩土工程学报，2013，35(2)：355-363. (HUANG Jieqing，XIE Xinyu，WANG Wenjun，et al. Study on one-dimensional nonlinear consolidation behavior for saturated soils with threshold gradient[J]. Chinese Journal of Geotechnical Engineering，2013，35(2)：355-363.(in Chinese))