基于有限元计算的重力坝可靠度及敏感性研究

发布时间：2018-02-13 06:23

本文关键词： 可靠度敏感性抗滑稳定有限元安全系数　出处：《西华大学》2015年硕士论文　论文类型：学位论文

【摘要】：重力坝是我国水利工程建设中常见坝型之一。混凝土重力坝主要靠自身重量产生抗滑力,最常见的破坏方式之一是滑动失稳,且破坏过程复杂。重力坝一旦滑动失稳会产生严重影响,并造成巨大的经济损失,因而大坝的安全稳定即核算重力坝坝体的抗滑稳定分析是重力坝设计的一项重要内容。传统安全系数法是抗滑稳定核算的重要计算方法,然而它在作结构设计时有其局限性和不科学性。它反映的是同一类型的某种受力状态下结构的安全度,但对不同类型结构或不同受力状态的同一结构同一截面来说,即使使用同一安全系数,也不能保证它们具有相同的安全度。其原因在于安全系数法忽略了客观上存在的各种设计变量的不确定性,只是把这些不确定量用一个笼统的K值掩盖起来。应用可靠度原理进行结构设计和校核,则可克服传统方法的不足之处。可靠度理论承认几乎所有的工程变量均为随机变量,以结构安全性与可靠性的各种量值(可靠度、可靠性指标)来设计或校核结构,并能通过灵敏度的计算获知各随机变量对结构安全影响的敏感程度,具有很好的应用前景。本文结合重力坝稳定开展可靠度计算和可靠度敏感性分析。首先,介绍了结构可靠度的基本原理,建立了适应于重力坝抗滑稳定的极限方程,得出了敏感度计算公式。接着,利用有限元软件建立了某水电站重力坝典型断面的有限元模型,分别计算出在三种不同工况下该重力坝的安全系数,分析其位移、有效应力和等效应力的分布规律,结合这三种工况下的可靠度核算结果评价该重力坝的整体安全度。然后,对影响该重力坝抗滑稳定的可靠度灵敏性的主要因素进行敏感性分析,评价各影响因素对可靠度的影响。最后对本文的研究进行总结和展望。
[Abstract]:Gravity dam is one of the common dam types in water conservancy construction in China. Concrete gravity dam mainly relies on its own weight to produce anti-slide force, and one of the most common failure modes is sliding instability. And the failure process is complicated. Once the gravity dam slips out of stability, it will have a serious impact and cause huge economic losses. Therefore, the calculation of dam safety and stability is an important content of gravity dam design, and the traditional safety factor method is an important calculation method for calculation of anti-slide stability. However, it has its limitations and unscientific features in structural design. It reflects the safety degree of the same type of structure under a certain stress state, but for the same section of the same structure with different types of structures or different stress states, Even if the same safety factor is used, there is no guarantee that they have the same degree of safety. The reason is that the safety factor method ignores the uncertainty of the various design variables that exist objectively. By using the reliability principle to design and check the structure, the shortcomings of the traditional method can be overcome. The reliability theory recognizes that almost all engineering variables are random variables. The structural safety and reliability values (reliability, reliability index) are used to design or check the structure, and the sensitivity of each random variable to the structural safety can be obtained by calculating the sensitivity. In this paper, reliability calculation and reliability sensitivity analysis are carried out in combination with gravity dam stability. Firstly, the basic principle of structural reliability is introduced, and the limit equation suitable for gravity dam anti-slide stability is established. The sensitivity calculation formula is obtained. Then, the finite element model of typical section of gravity dam of a hydropower station is established by using finite element software, and the safety factor of the gravity dam under three different working conditions is calculated, and its displacement is analyzed. The distribution of effective stress and equivalent stress, combined with the results of reliability calculation under these three conditions, is used to evaluate the overall safety of the gravity dam. The main factors influencing the reliability sensitivity of the gravity dam are analyzed, and the influence of the factors on the reliability is evaluated. Finally, the research of this paper is summarized and prospected.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV642.3

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