强震下深水桥梁群桩基础的动力响应及非线性损伤特性研究

发布时间：2018-01-06 04:43

本文关键词：强震下深水桥梁群桩基础的动力响应及非线性损伤特性研究　出处：《北京交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：群桩基础是深水桥梁结构中常见的一种桥梁下部基础结构形式,并且往往是地震中的易损部位和薄弱环节。动水效应是深水桥梁抗震设计中需要考虑的重要问题,不仅会改变深水桥梁的动力性态,也会对结构响应产生明显影响。本文以一座典型的深水桥梁为对象,基于流固耦合理论和方法,分别建立考虑结构-水体动力耦合作用的群桩基础弹性和非线性分析模型,讨论了Morison方程法、相关简化公式在桩身和承台的动水效应计算中的有效性。以此为基础,对深水桥梁群桩基础在近、远场地震作用下的响应特性和强震下的损伤分布规律进行了分析研究。主要内容包括： (1)采用势流体方法建立考虑流固耦合效应的深水桥梁群桩基础,对流体域宽度范围、流体域网格划分精度进行了讨论,明确了相关参数的取值,为后续研究奠定了重要数值基础。 (2)以基于势流体方法的群桩基础弹性分析模型为对象,以7条具有明显速度脉冲效应的近场地震波为输入,分析了不同水深下群桩基础的动力响应特性及桩间距的变化对其响应特性的影响。研究表明,随着水深的增加,结构自振周期不断延长,动水压力的存在使得群桩基础的动力响应显著增大。随着桩间距的增大,结构自振周期和动力响应都有减小的趋势。 (3)基于势流体全数值计算方法,检验了Morison方程法、王宝喜简化公式和魏凯简化公式在分别用于计算群桩基础的桩身和承台动水附加效应时的有效性,并对不同方法在位移、弯矩以及剪力等响应指标上的误差率进行了具体评价。 (4)建立群桩基础的非线性分析模型,选取成组近、远场地震记录为输入,对不同水深下群桩基础在近、远场地震下的动力响应和损伤分布规律进行了对比分析。结果表明,近场地震下深水桥梁群桩基础的动力响应及其损伤明显大于远场地震；承台底与桩顶的交界处是群桩基础的易损部位,在地面以下一定深度的土层交界处,桩身可能出现损伤破坏,且该损伤会随着地震强度的增强而向两端扩散。
[Abstract]:In this paper , based on the theory and method of fluid - solid coupling , a typical deep - water bridge is used as the object , which not only changes the dynamic state of the deep water bridge , but also has obvious influence on the structural response . ( 1 ) The deep water bridge group pile foundation considering the flow - solid coupling effect is established by using the potential fluid method , the range of the width of the fluid domain and the division precision of the grid of the fluid domain are discussed , the value of the relevant parameters is clarified , and the important numerical basis is laid for the subsequent study . ( 2 ) Based on the elastic analysis model of group pile foundation based on potential fluid method , the influence of dynamic response characteristics of pile foundation and the change of pile spacing on the response characteristics of pile foundation under different water depths are analyzed . ( 3 ) Based on the whole numerical calculation method of potential fluid , the validity of Morison equation method , the simplified formula of Wang Baoxi and the simplified formula of Weikai are tested , and the error rate of different methods in response indexes such as displacement , bending moment and shear force are evaluated . ( 4 ) The nonlinear analysis model of pile foundation is established , and the dynamic response and damage distribution law of the pile foundation of deep water bridge group under different water depths are compared and analyzed . The results show that the dynamic response and damage of pile foundation of deep water bridge group under near field earthquake are more than far field earthquake .

【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.15

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