双槽式渡槽结构地震反应分析

发布时间：2018-08-29 13:46

【摘要】：我国水资源总量较丰富,但人均和地均拥有量低,针对我国水资源时空分布不平衡的现状进行水资源优化配置。我国修建了一系列水资源联合调度工程,跨地区、跨流域调水工程用于解决区域性严重缺水问题和现状,目前我国最为宏大的调水工程属南水北调工程,其中东线、中线工程目前已经投入运行。在渠系建筑中渡槽作为一种交叉建筑物被广泛应用于输水调水工程中,为了满足大流量输水调水工程不仅发展了许多渡槽结构形式,并且随着结构设计、施工技术和材料强度等的发展,渡槽跨度和横断面不断加大,以至于槽体和槽内水体自重特别大。这种典型的“头重脚轻”结构在地震作用下,对渡槽结构抗震极为不利,并且还需考虑结构振动和水体晃动两者之间的相互作用,因此渡槽抗震成为抗震理论和技术上的难题之一。对大型双槽式渡槽的自振特性和地震反应的分析和研究是有其实践意义的,以期准确分析出通水渡槽在地震作用下水体晃动对槽身结构地震反应的影响,指导渡槽工程抗震。本文先介绍了渡槽抗震研究现状,阐述了流固耦合的基本理论和渡槽结构动力分析中四种常用的水体和结构简化方法及其适用范围。然后根据结构动力学基本原理整理出渡槽结构无阻尼自由振动的控制方程,并利用有限软件Midas Civil建立渡槽模型,采用附加质量法模拟水体作用进行空槽工况和满槽工况下的自振特性分析,两种工况下渡槽的振型基本一致,其中渡槽前10阶振型以横向平动和整体纵向平动为主,说明该渡槽在这两个方向的刚度较低,并且输水工况下的自振频率比空槽时的自振频率有所减小。最后依次介绍了三种地震反应分析方法,建立Midas Civil和ANSYS的渡槽模型,依据场地特征选取地震波,采用时程分析法进行渡槽结构的地震反应分析。两模型中最大位移存在差异,但两者一致体现出满槽工况时的横向位移大于空槽时的位移。对两种模型和两工况下的地震反应进行对比分析,从位移和应力情况相互验证,并可确定渡槽结构刚度情况和应力较大的区域。
[Abstract]:The total amount of water resources in China is relatively rich, but the per capita and local ownership is low, so the optimal allocation of water resources is carried out in view of the imbalance in the distribution of water resources in time and space. A series of water resources joint dispatching projects have been built in our country, which are used to solve the serious regional water shortage problem and the present situation of trans-regional and cross-basin water diversion projects. At present, the largest water transfer projects in China are the South-to-North Water transfer Project, among which the East Line, The middle line project has been put into operation at present. Aqueduct is widely used in water transfer projects as a cross structure in canal system buildings. In order to meet the needs of large discharge water transfer projects, many aqueduct structures have been developed, and along with the structural design, many aqueduct structures have been developed. With the development of construction technology and material strength, the span and cross section of aqueduct are increasing, so that the weight of tank and water body is very large. This typical "top-heavy" structure is extremely unfavorable to the earthquake resistance of aqueduct structure under earthquake, and the interaction between structural vibration and water sloshing should be considered. Therefore, seismic resistance of aqueduct has become one of the difficult problems in seismic theory and technology. It is of practical significance to analyze and study the natural vibration characteristics and seismic response of large double-channel aqueduct, in order to accurately analyze the influence of sloshing of aqueduct on the seismic response of aqueduct under earthquake, and guide the earthquake resistance of aqueduct engineering. In this paper, the present situation of seismic research on aqueduct is introduced, and the basic theory of fluid-solid coupling, four common simplified methods of water and structure in dynamic analysis of aqueduct structure and their application scope are described. Then, according to the basic principles of structural dynamics, the governing equations of the free vibration of aqueduct structure without damping are sorted out, and the aqueduct model is established by using finite software Midas Civil. The natural vibration characteristics of the aqueduct under the condition of empty channel and full tank are analyzed by the additional mass method. The vibration modes of the aqueduct under the two conditions are basically the same, in which the first 10 modes of the aqueduct are mainly transversely and longitudinally transversely. The results show that the stiffness of the aqueduct in these two directions is low and the natural vibration frequency of the aqueduct under the condition of water conveyance is smaller than that of the empty aqueduct. Finally, three kinds of seismic response analysis methods are introduced in turn, and the aqueduct models of Midas Civil and ANSYS are established. According to the site characteristics, the seismic wave is selected and the seismic response analysis of aqueduct structure is carried out by time-history analysis method. There are differences in maximum displacement between the two models, but both show that the transverse displacement of the full slot is larger than that of the empty slot. The seismic responses of the two models and under two working conditions are compared and analyzed. The displacement and stress are verified mutually and the region where the stiffness and stress of aqueduct structure are large can be determined.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV672.3;TV312

【相似文献】