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复杂地基与结构静、动力相互作用分析研究

The Study on Complex Foundation-structure Static and Dynamic Interaction

【作者】 张柏成

【导师】 李同春;

【作者基本信息】 河海大学 , 防灾减灾及防护工程, 2003, 硕士

【副题名】百色水电站进水塔与边坡相互作用分析

【摘要】 百色水电站位于珠江上游右江上,是多种综合效益的大型水利枢纽。进水塔在整个枢纽中起着极其重要的地位,它和进水口边坡的稳定安全与否将对整个枢纽的正常运行起关键作用。如何研究在复杂地基条件下进水塔与边坡的相互作用具有重要的理论意义和工程应用价值。 岩质边坡的稳定性不仅受到岩体内部地质结构因素的作用,还受到外界环境的影响,是多种因素的综合作用。如何分析它的稳定性是比较困难的。常用的边坡稳定分析方法中的极限平衡法由于采用了刚体假定以及块体间力的传递方向假定等,使得计算结果与实际出入较大且用于含有复杂地质条件的三维边坡问题非常困难。其它的岩质边坡分析方法虽然有各自的优点,但是在考虑各种荷载(如自重、渗流及地震等)的综合作用时,不如有限元法方便、有效。本文采用了合理模拟以夹层、结构面等为滑动面的薄层单元及相应的非线性分析为基础的三维非线性有限元解法来求解岩质边坡的稳定性。该方法被用于百色水利枢纽进水口边坡静、动力稳定计算。得出了该进水口边坡在施工和运行工况下是稳定的结论。 地基与结构的相互作用的分析方法有解析法和数值解法,目前常用的方法是有限元法和子结构法以及杂交法。当把地基与结构相互作用作为一个整体的力学问题来考虑时,分析中的关键环节就是两者相互作用界面上的接触问题。论文介绍了常用的接触面单元。本文针对百色水电站的地基和进水塔均是主要分析对象,而地基的地质条件十分复杂,提出了非一致网格位移协调解法。地基采用四面体单元和进水塔采用六面体单元。该方法以交界面上结构或地基相连一侧节点的位移变量作为基本变量,而另一侧节点的位移变量作为从变量,通过线性插值建立从变量与基本变量之间的线性关系,导出以基本变量作为未知量的总体线性方程组,从而在两者交界面处建立位移协调关系。 论文对目前常用的地基与结构动力相互作用的方法进行了归纳和总结,分析了各自的优缺点。针对百色水利工程实际情况,采用了振型分解反应谱法对进水塔进行了动力分析,得出了合理的结论。 论文采用三维非线性有限元法、非一致网格位移协调解法、振型分解反应谱法对复杂地质条件下的百色水电站进水口边坡与进水塔的相互作用进行了静、动力分析,得出了一些合理的结论,为今后类似的工程计算分析提供了一种可行的方法。

【Abstract】 Baise hydroelectric station lies on You river, which is a branch of Zhujiang river. It is a big all-around benefits hydro-junction. The role of intake tower is very important in the hydro-junction. The stability of intake tower and access ramp plays a key role in the failure-free operation of the hydro-junction. Considered the complexity of geological structure, how to study the interaction of intake tower and slope is important both in theoretical research and engineering.The stability of rock slope is affected both by the interior action of rock mass and by the exterior factors of environment. Its stability is the result of the multi-factors. So, it is difficult to analyze the stability of rock slope. At present, limit equilibrium method is one of the conventional slope stability analysis methods. The calculation results by the method don’t always conform to the facts, since the rigid body assumption and the assumed direction of inactive forces between slices in this method. Furthermore, it is difficult to analyze 3D slope with limit equilibrium method, considered the complexity of geologic structure. The other analysis methods of rock slope have respective advantages, but when many forces are considered (for example, gravitation, seepage force and earthquake force), these methods are as not convenient and effective as finite element method. 3D nonlinear finite element method is applied to analyze the stability of rock slope in the paper. When using this method, the thin layer element is used to simulate interlayer and structural joint for sliding surfaces. The static and dynamic analysis of intake slope of Baise hydroelectric station is calculated by this method. The stability of the intake slope during construction and operation are obtained in the paper.The analytical methods about foundation-structure interaction have two main categories. They are analytic methods and numerical methods. At present, finite element method, sub-structural analysis method and mixture method are common methods. When both foundation and structure are considered in analysis, interface problem on interface of them is keystone. Several common interface elements are described in the paper. When the foundation and the intake tower are both important analytical objects, and the geological condition of foundation is very complex, the slope is meshed with tetrahedral element, while the intake tower is meshed with hexahedral element. For this problem, compatible displacement method of different mesh is presented in the paper. On the interface of different mesh, nodes belonging tostructure or foundation are regarded as basic nodes, and nodes belonging to the other side are regarded as subordinate nodes. The linear interpolation relation between basic nodes and subordinate nodes is founded on the interface. So global linear equations are deducted. In these equations, unknown variables are basic nodes. Based on these assumptions, compatible displacement relation is founded on the interface of foundation and intake tower.The common methods of foundation-structure dynamic interaction are summarized and their advantages and shortages are analyzed in the paper. For Baise hydroelectric station, response spectrum of mode-superposition is applied in the dynamic analysis of intake tower. The rational conclusions are obtained.3D nonlinear finite element method, compatible displacement method of different mesh and response spectrum of mode-superposition are used to analyze the intake tower-intake slope static and dynamic interaction, since the complexity of geologic structure. The rational results provide a feasible way for the similar projects analysis in the future.

  • 【网络出版投稿人】 河海大学
  • 【网络出版年期】2003年 02期
  • 【分类号】TU470.3
  • 【被引频次】4
  • 【下载频次】337
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