【作者】 李勇泉；

【导师】 傅旭东；

【作者基本信息】 武汉大学 ， 岩土工程， 2010， 博士

【摘要】 只要有水存在的地方,应力场和渗流场就会相互影响、相互作用,处于一种复杂的动态变化过程中,构成了流固耦合关系。目前,在许多水工建筑的研究工作中,渗流分析和应力分析都是分开单独计算的,很少注重二者之间的耦合分析。在此情况下,把渗流场和应力场作为一个系统,探讨渗流场和应力场的耦合问题,是十分有必要的。本文在总结前人研究成果的基础上,主要研究和探讨了下面几个方面的内容：1.阐述了饱和-非饱和土渗流的基本理论,探讨了土-水特征曲线和渗透系数之间的关系及非饱和土渗透系数的确定方法,详细推导了三维空间的饱和-非饱和渗流的有限元基本格式,还分别阐述了土体渗流场应力场之间相互耦合的两种方法-间接方法和直接方法,分别给出了其基本方程及其有限元格式。2.详细介绍了二维平面应变比奥固结理论及其有限元形式,阐述了砂井地基的两类平面转换方法。结合江西城门山铜矿尾矿坝软基处理实践,采用修正剑桥渗流祸合模型有限元法对尾矿坝施工过程中砂井地基固结情况进行了数值模拟。分析了砂井地基中位移、孔隙水压力随时间的变化规律,并与实测结果进行了对比、分析,结果表明,测试期间内的位移的模拟值与实测值比较接近。3.介绍了渗流作用下的边坡稳定分析中的极限平衡法与强度折减有限元法的原理。二次开发了能考虑塑性变形、饱和度和孔隙比等对材料特性影响、土-水特性曲线并采用扩展的Mohr-Coulomb屈服准则的变形渗流耦合有限元模型。对洞庭湖区蓄洪垸堤防在水位骤降工况下非稳定渗流边坡的稳定性进行了计算,并对极限平衡Bishop法和强度折减有限元法计算结果进行了对比、分析。结果表明,水的渗透作用对边坡的最危险滑裂面具有一定的抬升作用,两种方法计算所得的浸润线、最危险滑裂面,安全系数相当接近,强度折减有限元法比极限平衡法更适合分析边坡的整体稳定性。4.简单阐述了土体的湿化变形以及湿化变形机理,对湿化变形的计算方法进行了一些探讨,结合算例,采用了非线性弹性模型,对土石坝的施工过程、湿化所引起的应力场、位移场的变化做了较为详细的分析和总结。更多还原

【Abstract】 If there is any water, stress field and seepage field will affect each other, will be in a couplingdynamic drift situation and form a coupling relation. At present, seepage analysis and stress analysis are calculated separately in research about the earth dam, hardly researched from the view of seepage-stress coupling. In this case, considering two fields as a system, it is essential to research and discuss the coupling problem between seepage field and stress field. On the basis of summarizing the the existing research, the thesis mainly covers the following aspects:1.The thesis first introduces soil moisture potential theory, then research and discuss the basic unsaturated seepage theory, the relation of soil-water characteristic curve and seepage coefficient and the confirmation of the material unsaturated seepage coefficient. The 3D saturated-unsaturated equations of porous media and the FEM are induced. Furthmore, direct seepage and stress coupling method and undirect seepage and stress coupling method are introduced, and their equations and FEM are given.2.The two-dimensional FEM format of Biot’s consolidation theory is detailedly deduced. two kinds of equivalent plane strain methods in drain pile ground are introduced. Based on the treatments of soft clay in tailing dam of Chengmenshan copper mining located in Jiangxi province, by using Modified Cam-clay Model Coupling Biot Theory, numerical simulation is carried out in drain pile ground during the construction of the tailings dam. Based on numerical results, relationships between the displacement of foundation and time, excess pore pressure of foundation and time, are analyzed. Comparing numerical results with observation by the displacements of the foundation, those calculated results have a good agreement with those observed results. those results gained by numerical method may provide reference to engineering practice.3.The principles of limit equilibrium methods (LEM) and shear strength reduction technique(SSRFEM) are introduced on stability analysis of soil slope under Seepage. the finite element modle under Coupled Deformation and Seepage Fields is developed, which takes into account the effect of plastic deformation, saturation and void ratio on the properties of soil materials, the effect of water and soil interaction and the extended Mohr-Coulomb failure criterion. the response of the soil slope of the Dongting Lake is simulated during rapid drawdown of water level. The results show that seepage upraises the critical slip surfaces. Furthermore, critical slip surfaces, saturation lines and safety factors by two ways are pretty close. the SSRFEM is more applicable to evaluating global stability of slopes than LEM.4.Soil slaking deformation and its mechanism are analyzed, and its calculating methods is discussed. And then, through some cases,applying nonlinearity elastic modle, give the discussions on the problems such as adding load in stages, influence on stress field and displacement field by slaking deformation, changes of stress field and displacement field by slaking deformation, changes of stress field and displacement field resulted from soil slaking deformation.更多还原