大气作用下膨胀土地基的水分迁移与胀缩变形分析  

Analysis of Water Migration and Deformation of Expansive-Soil Foundation under Atmospheric Influence

作　　者：赵艳林[1] 曾召田[1,2] 吕海波[1,2] 

机构地区：[1]广西大学土木建筑工程学院防灾减灾研究所,南宁530004 [2]桂林理工大学土木与建筑工程学院,广西桂林541004

出　　处：《防灾减灾工程学报》2011年第6期659-665,共7页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金(40702053);广西科技攻关项目(桂科能0815011-6-4);973前期研究专项(2010CB434810)资助

摘　　要：运用土体渗流和蒸发理论,建立了大气-非饱和土相互作用模型;以现场观测的气象数据作为边界条件,进行了地基土中水分迁移的数值模拟,得到了大气作用下地基土体含水量的动态分布规律。计算结果表明,地基土中含水量变化幅度随深度增加而递减,3.5 m深度以下土体的体积含水量基本不变,从而确定了南宁地区膨胀土地基的大气影响层深度为3.5 m。在此基础上,结合已有膨胀土胀缩性指标的干湿循环效应研究成果,提出了一种同时考虑干湿循环效应和1.0 m深处含水量变化的膨胀土地基胀缩变形计算方法,通过算例将该法与传统方法进行比较,结果显示该法更加符合工程实际。Based on the theory of soil seepage and evaporation,the interaction model of atmosphere-unsaturated soil is established.With the field observations of climate as the boundary conditions,numerical simulation of soil water migration in foundation is investigated to obtain the dynamic distribution of moisture content in foundation soil under atmospheric influence.The results show that the changes of soil water content in foundation decrease with the increase of the depth,and they are not affected by atmosphere below the depth of 3.5 m.So the depth of atmospheric influence on expansive soil foundation in Nanning is 3.5 m.On this basis,a method for deformation of expansive-soil foundation is proposed to consider the wetting-drying effect and the change of water contents at 1.0 m depth based on the research results of wetting-drying effect on shrink and expansion of expansive soil.By the aid of an engineering example,a comparison is made with the traditional method to illustrate that this new method is more suitable for engineering practice.

关 键 词：膨胀土 大气-非饱和土相互作用模型 水分迁移 地基胀缩变形 干湿循环效应 

分 类 号：TU443[建筑科学—岩土工程]