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1、摘要 I 论文题目 混凝土面板堆石坝面板开裂机理及效应研究论文题目 混凝土面板堆石坝面板开裂机理及效应研究 学科学科名名称称 水工结构工程 水工结构工程 摘摘 要要 混凝土面板堆石坝具有对不同地基条件适应性强 施工快 工期短 投资省等优 点 无论是大型还是中小型水电工程 都成为首选比较坝型 与碾压混凝土坝和高拱 坝并列成为最有发展前景的三类坝型 对混凝土面板堆石坝而言 面板 及其接缝止水 组成的防渗系统是大坝的主要防渗结构 面板的防裂问题是关系 到坝体安全和运行性 状的一个重要课题 我国在面板堆石坝建设 20 多年的时间里 取得了一定的成绩 但 也有一些失败的教训 西北口面板堆石坝的大量结构性
2、裂缝 株树桥面板堆石坝面板 的塌陷以及沟后面板砂砾石坝的垮坝等事故都昭示着我们 进行混凝土面板堆石坝面 板破坏机理及效应研究具有重要意义 目前 关于混凝土面板堆石坝面板应力变形的分析研究 主要集中在计算其在水 荷载和自重作用下的应力变形 而认为面板尺寸相对较小 将温度应力忽略不计 这 显然与混凝土面板堆石坝尤其是处于日温差和年温差较大的寒冷地区的面板坝面板的 实际应力变形情况不符 国内外关于面板堆石坝面板裂缝成因的研究结果表明 面板 裂缝尤其是贯穿性裂缝的产生主要是由于坝体的不均匀沉降及面板的温度应力共同作 用的结果 针对这方面问题 本文模拟混凝土面板堆石坝的施工过程 建立考虑面板 温度应力
3、水荷载及自重等情况的应力变形有限元计算模型 全面系统的研究混凝土 面板的应力变形特性 基于断裂力学的基本原理 分析混凝土面板裂缝的产生机理及 开裂过程 在充分掌握混凝土面板裂缝分布规律的基础上 预测分析了混凝土面板开裂情况 下堆石坝的渗流及应力变形特性 首先 针对面板缝隙的物理特性 以等宽缝隙水流 运动的规律为基础 研究建立了面板缝隙渗流 的计算模型 然后 以堆石体的孔隙率 为桥梁 对多孔岩土介质渗透系数与体积应变之间的数学表达式进行了推导 研究建立 了混凝土面板堆石坝渗流场与应力场耦合分析的数学模型 有限元计算模型 最后 应 用本文建立的计算模型 对公伯峡面板堆石坝进行了 渗流场 渗流场与应
4、力场耦合分 析有限元仿真计算 预测分析了假定的面板开裂情况下公伯峡混凝土面板堆石坝的渗 流场及应力变形分布规律 计算结果与实测结果的对比分析表明 本文的计算方法 与 计算模型是合理准确的 本论文的研究成果 可以方便 快速 准确地计算面板的应力变形分布规律 研究 分析面板裂缝产生的机理及破坏过程 预测分析面板开裂情况下 堆石坝的渗流与应力 西安理工大学博士学位论文 II 变形特性 是进一步研究混凝土面板堆石坝的理论基础 关键词 关键词 混凝土面板堆石坝 面板裂缝 开裂机理 渗流特性 应力变形特性 Title Research on the Mechanism and Effect of Conc
5、rete Face Rockfill Dam Cracking Major Hydraulic Structure Engineering Abstract III Name Li Yanlong Signature Supervisor Prof Li Shouyi Signature Prof Wang Ruijun Signature Abstract CFRD has a lot of advantages such as strong adaptability to the different soil conditions fast construction short const
6、ruction period less investment and so on whether large or small and medium hydropower projects CFRD has become the first choice of dam type comparison It is parallel to RCC and high arch dam which are the most promising three types of dam For CFRD face slab and joint sealing constitute the seepage s
7、ystem of main dam Face slab cracking problem is an important topic related to the dam safety and operation characteristics In our country there are some achievements are obtained in the construction of CFRD in the last 20 years but also some failures Many accidents such as large number of structural
8、 concrete cracks in the XIBEIKOU concrete face rockfill dam the collapse of ZHUSHUQIAO concrete face rockfill dam and the dam failure of GOUHOU concrete face rockfill dam are clear to tell us that it has great significances to research on the mechanism and effect of the face failure in CFRD At prese
9、nt the analysis of the stress and deformation in CFRD are mainly in the calculation of the stress and deformation under the loads of its weight and water press in which case the size of face slab is relatively small the temperature stress is negligible that is obviously difffreren from the actual st
10、ress and deformation of concrete face rockfill dam especially in the cold regions where the daily temperature difference and year temperature difference are very large The results of research on the resons of the face rockfill dam craks at home and abroad showed that face slab cracks especially pene
11、trating cracks are mainly due to both uneven settlement of the dam and the temperature stress of face slab Focusing on this problem simulating the construction process of concrete face rockfill dam in this paper the stress deformation finite element model is established which has considered temperat
12、ure stress weight and water press etc to comprehensively and systematically analysis the stress and deformation properties of concrete face slab The mechanism of concrete slab cracks and the cracking process are analysed based on the basic principles of fracture mechanics The stress and deformation
13、properties and seepage characteristic of rockfill dam are analysed and predicted based on fully grasping the distribution of cracks in concrete slab First according to the physical characteristics of face slab gap the calculation model of face slab gap 西安理工大学博士学位论文 IV flow is established based on th
14、e movement law of water flow in the equal width cracks Second use the porosity of rockfill as a bridge and deduce the mathematical expression between permeability coefficient of porous soil medium and volumetric strain And then the coupling analysis model of seepage stress and finite element model o
15、f CFRD are established Finally use the model established to calculate the seepage field and coupling analyse of seepage stress The stress deformation distribution law of Gongboxia CFRD is predicted in the case of hypothetical face slab cracks The comparative analysis of calculated and measured resul
16、ts show that the calculation method and calculation model is reasonable and accurate With the result of this paper the stress deformation distribution law can be calculated easily quickly and accurately Researching and analyzing the mechanism of the slab cracks and damage process of production predicting and analyzing the seepage and stress and deformation properties in the case of face slab cracks which are the theory foundation to the further study in CFRD Key words concrete face rockfill dam
