【作者】 王建新；

【导师】 王思敬； 王恩志；

【作者基本信息】 清华大学 ， 水利工程， 2010， 博士

【摘要】 降雨是诱发自然地质灾害发生以及诸多岩土体工程破坏失稳的主要原因之一。因此研究降雨非饱和入渗机理及其计算方法具有重要的意义。目前对于降雨非饱和入渗的机理认识以及计算方法的探讨都存在一些不足之处。首先无论试验研究还是模型理论的建立都没有对小降雨强度的自由入渗阶段给与足够的重视;其次传统建立在入渗量基础上的降雨入渗模型无法很好解决岩土体工程的渗透稳定性问题,即工程土体内渗透荷载以及负压变化规律;再次,现将降雨入渗作为一种边界条件来处理的计算方法不符合降雨的物理过程且会带来较大误差。因此,本文针从水势的角度对降雨非饱和入渗展开了试验研究,并在此基础上进行了理论模型和计算方法的研究,希望能为降雨条件下的岩土工程问题性问题提供新的思路和计算方法。本文以试验为基础,试验结果分析、机理研究、理论模型推导和数值计算方法相结合。首先设计了室内可精确控制雨强的降雨非饱和入渗试验装置,分别以粉土和粉砂土进行了包括自由入渗和压力入渗阶段的降雨试验,以及考虑了非饱和入渗参数影响的试验;基于试验结果从水势(负压)的角度对降雨非饱和入渗过程进行了描述,并进一步分析了降雨强度、非饱和入渗系数以及负压之间相互关系。现有的降雨非饱和入渗计算将降雨入渗的过程作为一种边界条件来处理的方法未能体现降雨入渗过程中几个关键物理量的变化关系及其随时间的变化关系。本文从负压的角度推导了降雨自由入渗和压力入渗模型,且应用降雨边界上的入渗模型联立计算方法来替代传统的边界条件处理方法。该方法符合降雨入渗的物理过程,且误差较小,具有较为明显的物理意义和很好的工程应用价值。本文发展了模型相应的数值计算方法,并结合已开发的降雨非饱和计算软件Unsat-Seepage,编制了相应的程序。应用本文的计算方法,对交河故城土遗址崖体在考虑降雨入渗条件下的稳定性问题进行了计算分析,验证了成果的正确有效性。更多还原

【Abstract】 Rainfall always induced catastrophic disasters and landslide, so it is a great significance of the study of rainfall infiltration mechanism and it is calculation methods. There are some shortages in current study about rainfall infiltration, the free seepage stage has always been neglected in study of rainfall experiments and theoretical models although the stage is very important to engineering seepage stability problems; it is reasonless that current calculation methods treat rainfall infiltration as a simple boundary, which not only brings more errors but also has not reflected the practical rainfall course. So the studies of rainfall unsaturated infiltration experiments、theoretical models and calculation methods have accomplished in this paper, hope to provide new research ways to rainfall infiltration stability problems of geotechnical engineering.The main works include tests of rainfall infiltration equipments、results analysis、theoretical models study and numerical calculation. The test equipment of rainfall infiltration has been designed firstly, which can exactly control rainfall intensity. Twelve tests has been done using different soils as specimen which to illustrate the mechanism of free and pressure infiltration stages from a point of view of suction, and the rainfall course has been definitely described. Furthermore, we analyzed the relationship of rainfall intensity soil unsaturated parameters and suction. Based on suction, we conducted the rainfall free and pressure infiltration models, they can tell the essence of rainfall infiltration, and the research developed relative calculation methods to take place of the current method treating the rainfall infiltration as a boundary. All these works not only have clearly practical significance and good precision, but also is well adapt to engineering application.The paper design the relative numerical calculation method based on the rainfall infiltration theoretical models we conducted, combining with rainfall infiltration compute program Unsat-Seepage, the computer codes have been developed to study the rainfall infiltration and its’engineering application. As an elucidation, the stability problems of Ruins of Jiaohe slopes under rainfall infiltration have been simulated, using the method developed the paper. The result showed that all works of the paper are more applicable and reasonable.更多还原