混合坝刺墙应力场与渗流场耦合作用数值分析

发布时间：2018-08-19 20:28

【摘要】：混合坝是由混凝土坝和土石坝共同组成的坝型,土石坝作为挡水坝段、而混凝土坝兼有挡水和溢流的作用,这种坝型能充分利用当地地形条件,降低工程造价。但是混凝土与土石坝刚度差别较大,应力和渗流条件较复杂,在两种坝型的连接部位较为薄弱,接头部位的安全关乎全局,必须妥当处理。渗流与应力是相互联系相互作用的,二者的耦合计算是目前岩土工程研究的热门话题。岩土介质的互相影响体现在二者的耦合系统,因此在进行渗流计算时把应力考虑进来也是十分必要的。通过介绍国内外已建混合坝工程实例,结合混合坝的形式和特点,归纳出混合坝研究及发展现状。从渗流达西定律基本理论出发,对饱和渗流的基本理论、土体渗透系数及材料非饱和渗透系数进行了研究,以压力水头为未知量,导出多孔土体介质的饱和非饱和渗流的基本微分方程和其有限元应用的数学模型。结合土石坝应力分析的邓肯张本构模型,进行ANSYS的二次开发,并实现土石坝分层填筑的有限元模拟。以出山店水库挡水坝段中的连接坝段为例,建立了连接段的三维有限元模型,介绍了插入式混合坝的建模思路和网格划分方法,提取应力、渗流计算所需的节点、单元、集合、约束等信息。最后对应力和渗流的计算结果进行相互迭代来实现耦合,对比考虑耦合与不考虑耦合情况下的渗流场的渗流量、渗流梯度等渗流要素。
[Abstract]:The mixed dam is composed of concrete dam and earth-rock dam. The earth-rock dam is used as the water retaining dam section, and the concrete dam has the functions of water retaining and overflow. This dam type can make full use of the local topographic conditions and reduce the project cost. However, the stiffness of concrete and earth-rock dam is quite different, the stress and seepage conditions are more complex, and the connection part of the two types of dam is relatively weak. The safety of joint part is related to the overall situation and must be properly dealt with. Seepage and stress are interrelated and interacted. The coupling calculation of seepage and stress is a hot topic in geotechnical engineering. The interaction of rock and soil media is reflected in the coupling system, so it is necessary to take stress into account in seepage calculation. By introducing the examples of the construction of hybrid dams at home and abroad and combining the forms and characteristics of hybrid dams, the research and development status of hybrid dams are summarized. Based on the basic theory of Darcy's law of seepage, the basic theory of saturated seepage, the permeability coefficient of soil and the unsaturated permeability coefficient of materials are studied. The basic differential equation of saturated unsaturated seepage in porous soil and the mathematical model of its finite element application are derived. Combined with Duncan Zhang Ben model of earth-rock dam stress analysis, the secondary development of ANSYS is carried out, and the finite element simulation of layered fill of earth-rock dam is realized. Taking the connecting dam section of Qiongshandian Reservoir as an example, the three-dimensional finite element model of the connection section is established, and the modeling idea and mesh division method of the inserted hybrid dam are introduced. The nodes, units and sets needed for stress extraction and seepage calculation are introduced. Constraints, etc. Finally, the calculation results of stress and seepage are iterated to realize the coupling. The seepage flow, seepage gradient and other seepage elements are compared between the coupling and the non-coupling.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV223.4

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