【作者】 张存慧；

【导师】 马震岳； 张运良；

【作者基本信息】 大连理工大学 ， 水利水电工程， 2010， 博士

【摘要】 随着“西部大开发”、“西电东送”战略的实施,随着电力资源的日益短缺,一大批巨型水电工程开始陆续新建。水电站厂房结构作为水利枢纽中的重要组成部分,其安全性逐渐受到重视。本文以某大型水电站700MW级机组为工程背景,在理论分析的基础上,采用数值计算方法,对电站厂房结构的静动力非线性特性和流固耦合特性等进行了详细研究。相关的计算理论、计算方法以及结论,可为今后类似问题的研究提供技术依据和参考。论文具体包括以下几部分内容：(1)在详细分析现有关于直埋式蜗壳结构研究现状的基础上,建立考虑蜗壳钢衬与外围混凝土间摩擦接触的非线性数值模型,并考虑混凝土材料的拉伸软化和拉伸损伤特性。分析直埋式蜗壳结构在施加一次内水压力等静荷载作用下的受力状态；在蜗壳外围混凝土发生塑性损伤基础上,对座环柔度进行复核,并与线弹性计算结果进行对比分析。建立多个有限元计算模型,分析蜗壳上、下部结构对蜗壳外围混凝土的损伤、钢部件应力以及座环柔度值的影响。对厂房整体结构进行内水压力往复加卸载时的数值计算,分析了结构在服役期内的受力状态。(2)在直埋式蜗壳外围混凝土结构发生静态损伤的基础上(施加一次内水压力),对电站厂房结构进行脉动水压力荷载作用下的振动响应分析,对蜗壳外围混凝土在脉动水压力荷载作用下的损伤演化、结构典型部位的最大应力状态、钢部件的疲劳特性等内容进行研究,并依据相应建议值对厂房结构的振动响应进行评价。分析了直埋式蜗壳外围混凝土结构发生不同程度的损伤开裂后(包括假定材料为线弹性；对结构施加一次内水压力,蜗壳外围混凝土发生损伤开裂；对结构施加内水压力循环荷载,蜗壳外围混凝土发生损伤开裂),对厂房整体结构动力特性的影响。(3)验证了无限单元作为动力人工边界,进行地震动分析时,所采用地震动输入方法的正确性。进而对地基部分有限离散区域范围的敏感性进行分析。在上述因素明确的情况下,采用有限元与无限元耦合模型模拟水电站厂房的无穷域地基。在静力非线性计算的基础上,对电站厂房整体结构进行设计地震动作用下的动力非线性计算。主要分析了静动态荷载作用下,蜗壳外围混凝土的损伤演化、各典型部位的动应力状态以及振动位移、振动速度、振动加速度等。对电站厂房结构开展了地震动超载响应分析,并与设计地震动时的计算结果进行对比,重点从混凝土结构的损伤、钢部件的应力峰值等指标进行安全评价。(4)建立不同的数值计算模型,分析了蜗壳外围混凝土损伤开裂对电站厂房局部、整体结构自振特性的影响,并选取合理模型进行共振复核,从共振复核的角度对厂房的安全性进行评价。(5)采用ADINA软件提供的基于势的流体单元(Potential-based fluid elements)模拟水电站厂房流道系统内的水体,对结构进行自振特性和地震动作用下的动态响应计算,并与不考虑流道内水体的计算结果进行对比,分析了流道系统内流体对结构动力特性的影响。更多还原

【Abstract】 With the shortage of the power resource day by day, and the strategy of Western Development and Power Transmission from West to East implemented, a great deal of huge hydroelectric projects have been constructed. Safety and stability of the hydro-power house, an important part of the hydroelectric project, has been paid more attention to. Static and dynamic nonlinear characteristic and fluid-structure interaction characteristic of the hydro-power house were studied through theory analysis and numerical simulation in this paper. The relevant calculation theory, methods and conclusions could provide technical support and reference for similar problems. The paper includes the following sections:Firstly, base on the current research, the nonlinear numerical model of directly embedded steel spiral case was made considering the elastic contact behavior occurring between the steel liner and the surrounding concrete, and the tension softening and damage characteristic of the concrete. The stress state of the spiral case was analyzed under the static loads such as internal water pressure. The flexibility of the stay rings was checked on the basis of plastic damage model of the concrete, which was compared with that of the linear elastic model. Through the resultant comparison of different FEM models, the existing influence of the super-& sub-structures of the spiral case was studied according to damage evolution of the surrounding concrete, steel liner stresses and flexibility of the stay rings. Furthermore, the stress state of the overall hydro-power house was studied through the numerical simulation under the repeated loading of internal water pressure.Secondly, the dynamic response of the hydro-power house under the pulsation water pressure load was studied including the fatigue characteristic of the steel liner, and the stress state and damage evolution of the surrounding concrete, after the static damage of the surrounding concrete of the spiral case appeared. The dynamic safety of the power house was evaluated according to the above analysis and the relevant rules. What’s more, the influence upon the dynamic characteristic of the whole power house caused by damage or crack of the surrounding concrete of the spiral case under different degree was analyzed by the comparison of the linear elastic model, the model considering concrete damage or crack under once or repeated internal water pressure loading and so on.Thirdly, the ground motion input method was verified, which uses the infinite elements as dynamic artificial boundary, and the range sensitivity of the finite discrete region was analyzed. So the hydropower house infinite foundation was simulated by the coupling model of the finite and infinite element (FE-IE). After the static nonlinear analysis, the resultant data of the whole power house was obtained under the design ground motion by dynamic nonlinear simulating. The damage evolutions, dynamic stresses, vibration amplitudes, velocity and acceleration of the surrounding concrete of the spiral case were studied. Furthermore the response of the power house was analyzed under the seismic overloading conditions and compared with that of the design seismic loads conditions. The concrete damage and steel liner stresses were evaluated.Fourthly, different numerical models of the powerhouse, partial and overall models, were established, and the natural vibration characteristic was analyzed taking the damage or crack of the surrounding concrete of the spiral case into consideration. Following, a reasonable model was selected to check the resonance probability, and finally the security of the powerhouse was evaluated.In the last section, the potential-based fluid elements in ADINA software were used to simulated the fluid in the flow passage of the hydropower house. The natural vibration characteristic and seismic response are calculated by using FEM. The results were compared with those obtained by the model without the fluid, and the effect of the fluid in flow passage on the structure dynamic characteristic is analyzed.更多还原