压实膨胀土非饱和渗水系数函数的密度与水力滞回效应

周葆春; 陈志

doi:10.11779/CJGE201910003

压实膨胀土非饱和渗水系数函数的密度与水力滞回效应 English Version

周葆春,
陈志

信阳师范学院建筑与土木工程学院,河南信阳 464000

基金项目: 国家自然科学基金面上项目（11772290）; 河南省高等学校重点科研项目（17A560008）; 信阳师范学院“南湖学者奖励计划”青年项目

详细信息

作者简介:
周葆春(1978—),男,博士,教授,主要从事非饱和土与特殊土力学方面的研究。E-mail:zhoubc@xynu.edu.cn。

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出版历程
- 收稿日期: 2018-07-01
- 发布日期: 2019-10-24

Effects of density and hysteresis on hydraulic conductivity function of compacted expansive soil

College of Architecture and Civil Engineering, Xinyang Normal University, Xinyang 464000, China

摘要

摘要: 为探讨密度与水力滞回对膨胀土非饱和渗水系数函数（hydraulic conductivity function, HCF）及非饱和渗流的影响,以压实弱膨胀土为研究对象,开展变水头渗透试验获得饱和渗透系数-孔隙比e关系。基于van Genuchten-Mualem（VGM）模型,采用TRIM（transient release and imbibition method, 瞬态脱湿与吸湿）试验方法获得6种密度下脱/吸湿过程的HCF模型参数α,n,并构建α,n与e的经验公式。基于所获HCF模型参数在Hydrus中开展降雨入渗数值分析。结果表明：①土体密度与水力滞回对α,n影响显著;无论脱/吸湿过程,α,n均随e增大而增大;相同密度下,脱湿过程α,n均小于吸湿过程对应值。② 密度与水力滞回均对吸力表达的HCF影响显著;不同e下HCF存在“交叉”现象：相同吸力下,交叉点前,密度小的试样渗水系数k值大;交叉点后,密度大的试样k值大;同一密度相同吸力下脱湿过程k值明显大于吸湿过程k值。③ 密度对体积含水率θ表达的HCF影响显著,相同θ下,密度大的试样k值小,但不存在“交叉”现象;水力滞回对θ表达的HCF影响微弱,同一密度下脱/吸湿过程HCF接近。④ 数值分析表明,土体密度对非饱和渗流影响显著,但密度变化对湿润锋前进速度快慢影响不具单调性;水力滞回对渗流分析结果影响明显;采用形式简单的HCF模型如VGM模型,采用α,n与e的经验公式,对不同密度、不同脱/吸湿路径采用对应的模型参数值,是综合考虑密度与水力滞回对非饱和渗流影响的可行方法。
- 非饱和渗水系数函数 /
- van Genuchten-Mualem模型 /
- 水力滞回 /
- TRIM试验方法 /
- 渗流分析
Abstract: The effects of density and hysteresis on the hydraulic conductivity function (HCF) of Jingmen compacted expansive soil are experimentally investigated. The saturated hydraulic conductivities over the range of void ratio from 0.476 to 1.624 are determined by the falling head permeability test. The parameters of the commonly adopted HCF model, van Genuchten-Mualem (VGM) model under six different densities and drying/wetting paths are measured by using the transient release and imbibition method (TRIM). The conclusions are drawn as follows: (1) The parameters α, n of the VGM model increase with the increase of void ratio, and their values under drying path are less than the corresponding ones under wetting path. (2) The effects of density and hysteresis on the relationship between hydraulic conductivity (k) and matric suction are significant. HCFs intersect under different densities. The value of k under lower density is larger before the intersection of HCFs, and that under higher density is larger after the intersection. The value of k under drying path is larger than that under wetting path. (3) The effects of density on the relationship between k and volumetric water content θ are significant. The value of k under higher density is smaller than that under lower density, and HCFs do not intersect under different densities. The effects of hysteresis on the relationship between k and θ are not significant. (4) One-dimensional vertical infiltration is simulated using the Hydrus with the above-mentioned parameters of VGM model. The results show that the effects of density on seepage are remarkable. But the influences of density on wetting front velocity are not monotonic. On the other hand, whether to account for hysteresis leads to significant difference of the simulated results. The empirical formulas for parameters α, n and e of VGM model under different wetting/drying paths can be used in seepage modeling to account for the effects of density and hysteresis.
- hydraulic conductivity function /
- van Genuchten Mualem model /
- hydraulic hysteresis /
- TRIM method /
- seepage analysis

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参考文献(22)

[1]	程鹏, 李锦辉, 宋磊. 生态边坡的水力和力学特性分析:试验研究[J]. 岩土工程学报, 2017, 39(10): 1901-1907. (CHENG Peng, LI Jin-hui, SONG Lei.Hydraulic and mechanical characteristics of ecological slopes: experimental study[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(10): 1901-1907. (in Chinese))
[2]	陶高梁, 孔令伟. 基于微观孔隙通道的饱和/非饱和土渗透系数模型及其应用[J]. 水利学报, 2017, 48(6): 702 - 709.(TAO Gao-liang, KONG Ling-wei. A model for determining the permeability coefficient of saturated and unsaturated soils based on micro pore channel and its application[J]. Journal of Hydraulic Engineering, 2017, 48(6): 702-709. (in Chinese))
[3]	倪沙沙, 迟世春. 基于粒子群支持向量机的高心墙堆石坝渗透系数反演[J]. 岩土工程学报, 2017, 39(4): 727-734. (NI Sha-sha, CHI Shi-chun.Back analysis of permeability coefficient of high core rockfill dam based on particle swarm optimization and support vector machine[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(4): 727-734. (in Chinese))
[4]	谢定义. 非饱和土土力学[M]. 北京: 高等教育出版社, 2015. (XIE Ding-yi.Soil mechanics for unsaturated soils[M]. Beijing: Higher Education Press, 2015. (in Chinese))
[5]	SL237—1999 土工试验规程[S]. 1999. (SL237—1999 Specification of soil test[S]. 1999. (in Chinese))
[6]	CAI G, ZHOU A, SHENG D.Permeability function for unsaturated soils with different initial densities[J]. Canadian Geotechnical Journal, 2014, 51(12): 1456-1467.
[7]	American Society for Testing and Materials. ASTM D7664—10 Standard test methods for measurement of hydraulic conductivity of unsaturated soils[S]. 2010.
[8]	FREDLUND D G, RAHARDJO H, FREDLUND M D.Unsaturated soil mechanics in engineering practice[M]. Hoboken: John Wiley & Sons, Inc, 2012.
[9]	MUALEM Y.A new model for predicting the hydraulic conductivity of unsaturated porous media[J]. Water Resources Research, 1976, 12(3): 513-522.
[10]	VAN GENUCHTEN M T. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal, 1980, 44(5): 892-898.
[11]	ŠIMŮNEK J, VAN GENUCHTEN M T, ŠEJNA M. Recent developments and applications of the hydrus computer software packages[J]. Vadose Zone Journal, 2016, 15(7): 1-25.
[12]	KOOL J B, PARKER J C.Development and evaluation of closed-form expressions for hysteretic soil hydraulic properties[J]. Water Resources Research, 1987, 23(1): 105-114.
[13]	LENHARD R J, PARKER J C, KALUARACHCHI J J.Comparing simulated and experimental hysteretic two-phase transient fluid flow phenomena[J]. Water Resources Research, 1991, 27(8): 2113-2124.
[14]	WEI C, DEWOOLKAR M M.Formulation of capillary hysteresis with internal state variables[J]. Water Resources Research, 2006, 42(7): W07405.
[15]	HU R, CHEN Y F, LIU H H, et al.A water retention curve and unsaturated hydraulic conductivity model for deformable soils: Consideration of the change in pore-size distribution[J]. Géotechnique, 2013, 63(16): 1389-1405.
[16]	LIKOS W J, LU N, GODT J W.Hysteresis and uncertainty in soil water-retention curve parameters[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(4): 04013050.
[17]	WAYLLACE A, LU N.A transient water release and imbibitions method for rapidly measuring wetting and drying soil water retention and hydraulic conductivity functions[J]. Geotechnical Testing Journal, 2012, 35(1): 103-117.
[18]	LU N, GODT J W.斜坡水文与稳定[M]. 北京: 高等教育出版社, 2014. (LU N, GODT J W.Hillslope hydrology and stability[M]. Beijing: Higher Education Press, 2014. (in Chinese))
[19]	孔令伟, 周葆春, 白颢, 等. 荆门非饱和膨胀土的变形与强度特性试验研究[J]. 岩土力学, 2010, 31(10): 3036-3042. (KONG Ling-wei, ZHOU Bao-chun, BAI Hao, et al.Experimental study of deformation and strength characteristics of Jingmen unsaturated expansive soil[J]. Rock and Soil Mechanics, 2010, 31(10): 3036-3042. (in Chinese))
[20]	周葆春, 张彦钧, 汤致松, 等. 不同压实度荆门弱膨胀土的一维膨胀–压缩特性[J]. 岩土力学, 2014, 35(5): 1275-1283. (ZHOU Bao-chun, ZHANG Yan-jun, TANG Zhi-song, et al.One-dimensional swelling-compression characteristics of Jingmen weak expansive soil under different compactnesses[J]. Rock and Soil Mechanics, 2014, 35(5): 1275-1283. (in Chinese))
[21]	周葆春, 孔令伟, 郭爱国. 荆门弱膨胀土的胀缩与渗透特性试验研究[J]. 岩土力学, 2011, 32(增刊2): 424-429. (ZHOU Bao-chun, KONG Ling-wei, GUO Ai-guo.Experimental study of swelling-shrinkage behaviour and permeability characteristics of Jingmen weak expansive soil[J]. Rock and Soil Mechanics, 2011, 32(S2): 424-429. (in Chinese))
[22]	LIKOS W J, YAO J.Effects of constraints on van Genuchten parameters for modeling soil-water characteristic curves[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(12): 06014013.