【作者】 张萍；

【导师】 刘德富；

【作者基本信息】 武汉大学 ， 水工结构工程， 2010， 博士

【摘要】 拱梁分载法目前仍然是拱坝结构分析的主要方法,但在采用拱梁分载法进行应力分析时,需要合理确定各计算高程坝基岩体的变形模量和泊松比。而拱坝大多建在多种岩石组成的岩基上,坝基的综合变形参数不仅与各单层岩体的变形参数有关,还与各岩性岩体的厚度比例、岩层倾角等有关,用其中任何一种岩性岩体的变形参数来代替或者对所有岩体变形参数进行简单的平均都是不合理的,因此有必要探讨更加合理的拱坝地基综合变形参数的确定方法。拱坝是一高次超静定空间壳体结构,荷载主要通过拱的作用传到两岸基岩上去,因此拱坝对河谷两岸地形地质条件的要求非常高。但往往客观条件不能满足要求,因此须采取相应的地基处理及结构措施,使其满足设计要求。但如何进行地基处理,使其达到既节省投资又对大坝安全较为有利,目前还没有一种好的方法。本文结合世界最高的锦屏一级拱坝,从理论及方法上探讨了拱坝地基综合变形参数三维有限元求解方法；建立了在地基综合变形参数多目标优化的模型和方法；结合优化分析和敏感性分析,提出了拱坝基础地基处理优化方案,初步探索并形成了一个从地基综合变形参数的求解到结合优化分析确定基础处理方案的体系,主要内容如下：(1)综述了细观力学中确定复合材料等效变形模量的几种常见方法,提出了利用三维有限元计算成果确定坝基综合变形参数的方法,计算的结果与细观力学中的理论求解结果比较表明,推荐的方法合理可行。(2)充分考虑锦屏拱坝坝址附近的断层、软弱带、置换混凝土以及固结灌浆深度的基础上,建立了锦屏一级拱坝的三维有限元计算模型,利用本文提出的方法确定了锦屏一级拱坝各个高程的综合变形参数,对拱坝进行了应力和变形分析。(3)利用多目标线性规划理论建立坝基变形模量优化的数学模型,该模型分别以拱梁分载法和有限元等效应力法作为应力重分析的方法,以不同高程地基综合变形模量E为设计变量,在人为可以改变地基综合变形模量的范围内,利用多目标线性规划的方法寻求一组对坝体应力、稳定及变形最优、相对基础处理费用又较低的地基综合变形模量。(4)对锦屏一级拱坝应力对地基综合变形参数变化的敏感性进行了分析,在一定范围内浮动改变基础变形模量,一方面反映坝基变形模量的改变对坝体应力的影响,另一方便也反映出拱坝对坝基变形模量变化的适应能力。在优化分析及敏感性分析的基础上,推荐了新的锦屏一级拱坝地基处理方案。更多还原

【Abstract】 Arch-cantilever method is still the main method of arch dam structural analysis. The deformation modulus and poisson’s ratio of dam foundation rock in different elevation need to be properly determined by using the arch-cantilever method for stress analysis. Most of the arch dam is built on rock foundation composed of a variety of rock, so the comprehensive deformation parameters of the foundation is not only concerned with the single rock mass deformation parameters, but also with the ratio of the thickness and strata dip, which is unreasonable by using any a kind of rock deformation parameters instead of rock mass deformation parameters, or simple average all the rock mass deformation parameters. It is necessary to explore more rational method for calculting the comprehensive deformation parameters of the arch dam foundationHigh arch dam is a high indeterminate space shell structures. It is very strict with the topographic and geologic conditions on the valley sides because the arch dam load is primarily passed to the both sides by the arch effec. In fact, the objective condition often is not satisfied with the requirements, so some appropriate measures for foundation treatment and structure should be taken to meet the design requirements. It is still not a good way to draft the foundation reinforcement scheme with less cost and more favorable for dam safetyIn this paper, the comprehensive deformation parameters calculation method for the world’s highest Jinping arch dam is proposed based on finite element method, the multi-objective optimization models on foundation deformation parameters is established, and a new foundation treatment scheme based on optimization analysis and sensitivity analysis is put forward. A system from calculting comprehensive deformation parameters to determining foundation treatment measures based on optimization analysis is formed. Such as the major content:(1)The common method of calculting composite materials equivalent deformation parameters in micromechanics is summarized, and the method of calculting the foundation deformation parameters are proposed by the results of three-dimensional finite element method. It shows this method is reasonable by comparing the result with the theoretical solution in micromechanics.(2)Three-dimensional finite element model is established by considering faults, weak zone, concrete replacement and grouting depth in the vicinity of Jinping arch dam, the Jinping arch dam comprehensive deformation parameters is computed by using the proposed method, and stress and deformation analysis is also carried out.(3)Mathematical optimization model on foundation deformation modulus is established by using multi-objective linear programming theory. In this model, the arch-cantilever method and finite element method as the stress re-analysis method, the foundation deformation modulus E as the design variables, the multi-objective linear programming method is used to find a group foundation deformation modulus which is the best for dam stress, stability, deformation and foundation treatment cost within the foundation deformation modulus’s man-made changing range.(4)Stress sensitivity analysis on Jinping arch dam concerning the foundation deformation parameters is carried out. It shows the influence on arch dam stress and the arch dam adaptability with the changing foundation deformation modulus whiles the foundation deformation modulus floating within a certain range. Based on optimization analysis and sensitivity analysis, new Jinping arch dam foundation treatment scheme is given.更多还原