非饱和石灰改良黄土的渗水系数预测

doi:10.11779/CJGE2020S2005

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摘要针对黄土地区大部分黄土处于非饱和的状态,采用石灰改良非饱和黄土以解决非饱和黄土渗透性的问题。利用非饱和固结仪测得压实黄土和石灰改良黄土的土水特征曲线,采用Van Genuchten模型对试验数据进行拟合,同时测得饱和压实黄土和石灰改良黄土的饱和渗水系数,基于测得的土水特征曲线,采用Childs & Collis-George预测非饱和石灰改良黄土的渗水系数的模型,得到非饱和石灰改良黄土的体积含水率以及基质吸力和渗水系数之间的关系曲线,并通过微观结构来分析验证其机理。结果表明：压实度对非饱和石灰改良黄土土水特征曲线影响明显,压实度越大,进气值越大;石灰改良黄土的饱和渗水系数小于压实黄土;同一压实度,非饱和石灰改良黄土的渗水系数随体积含水率的增大而增大,随基质吸力的增大,呈先迅速减小后趋于平衡的趋势,吸力一定时,压实度越大,非饱和渗水系数越小;且渗水系数与基质吸力可用幂函数表示。为石灰改良黄土地基和路基等工程提供数值计算基础和理论支持。

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关键词 ：非饱和土, 石灰改良黄土, 土水特征曲线, 渗水系数, 基质吸力

Abstract：In view of the fact that most loess in the loess regions is in an unsaturated state, lime is used to improve the unsaturated loess to solve the problem of permeability of unsaturated loess. The soil-water characteristic curves of the compacted loess and the lime-modified loess are measured by an unsaturated consolidation instrument, and the Van Genuchten model is used to fit the test data. The saturated permeability coefficients of the saturated compacted loess and the lime-modified loess are also measured. The obtained soil-water characteristic curve is modeled using the Childs & Collis-George model to predict the permeability coefficient of unsaturated lime-improved loess, and the relationship curves of the volumetric water content of unsaturated lime-improved loess, the matrix suction and the permeability coefficient are obtained so as to analyze the mechanism. The results show that the compaction degree has a significant effect on the soil-water characteristic curve of the unsaturated lime-modified loess. The larger the compaction degree, the larger the air intake value. The saturated permeability coefficient of the lime-modified loess is smaller than that of the compacted loess. Under the same compaction degree, the permeability coefficient of the lime-improved loess increases with the increase of the volumetric water content, and with the increase of the matrix suction, it first decreases rapidly and then tends to be equilibrium. When the suction is constant, the greater the compaction degree, the smaller the unsaturated permeability coefficient. The permeability coefficient and matrix suction can be expressed by a power function. The results may provide numerical calculation basis and theoretical support for lime-improved loess and roadbed projects.

Key words： unsaturated soil lime-modified loess soil-water characteristic curve water permeability coefficient matrix suction

收稿日期: 2020-08-10

ZTFLH:

TU444

基金资助:陕西省自然科学基础项目（2017JM5059）; 陕西省黄土力学与工程重点实验室项目（13JS073）

通讯作者: *（E-mail:1315478559@qq.com）

作者简介: 胡再强(1964— ),男,教授,博士生导师,主要从事黄土力学与工程研究工作。E-mail: huzq@xaut.edu.cn。

引用本文:

胡再强, 梁志超, 郭婧, 冯哲, 王凯, 折海成. 非饱和石灰改良黄土的渗水系数预测[J]. 岩土工程学报, 2020, 42(s2): 26-31. HU Zai-qiang, LIANG Zhi-chao, GUO-Jing, FENG-Zhe, WANG-Kai, SHE Hai-cheng. Prediction of permeability coefficient of unsaturated lime-improved loess. Chinese J. Geot. Eng., 2020, 42(s2): 26-31.

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http://manu31.magtech.com.cn/Jwk_ytgcxb/CN/10.11779/CJGE2020S2005 或 http://manu31.magtech.com.cn/Jwk_ytgcxb/CN/Y2020/V42/Is2/26

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