桩土相互作用下高桩码头随机地震反应分析

发布时间：2018-06-01 12:39

本文选题：地震激励 + 高桩码头　；参考：《重庆交通大学》2014年硕士论文

【摘要】：高桩码头是我国港口建设中常用的码头结构型式，在港口建设和发展中有着重要作用。历次震害表明，高桩码头结构极易遭受地震破坏，因此在其设计使用年限内是否拥有足够的抗震能力非常重要。本文考虑桩-土相互作用，以随机过程作为地震动输入，对高桩码头随机地震响应特征进行分析，主要研究内容及成果如下：（1）对常用地震动输入和桩-土接触模拟方法进行了总结，并参考建筑抗震设计规范（GB50011-2010）和前人的研究成果获得相关参数，以大型通用有限元软件ABAQUS为平台，建立了高桩码头的二维有限元模型。（2）对该有限元模型进行结构自振分析，计算了高桩码头结构的模态振型，确定了结构的振动特性及所需模态阶次。（3）考虑桩-土相互作用，对高桩码头结构进行了反应谱分析，获得了三种不同方向地震激励作用下结构的位移及应力曲线。并对所得的曲线进行分析发现：在水平地震激励作用下码头结构向前倾覆，竖向地震激励作用下码头结构整体向前水平移动，水平激励对土体和结构的变形起主导作用。（4）对高桩码头有限元模型进行随机地震响应分析，，得出了在随机地震激励下结构响应位移及拉应力的功率谱曲线。随后，对拉应力响应的功率谱曲线进行分析，得到了其在概率保证为75%的置信区间内的拉应力均方根值。依此可以确定，码头节点的相对位移功率谱曲线的峰值均出现在较小频率处，且高阶振型对结构响应的影响有限。（5）将反应谱分析与随机地震响应分析结果进行比较，可看出，两者所得位移及应力曲线变化趋势较为一致，且数量级相同。只是两者在数值上有所差异，其中，反应谱分析所得到的应力最大值较大。据此可确定，反应谱分析相对较为保守，而对工程实例进行功率谱分析是十分必要的。（6）在地震作用下，对结构地震响应的影响因素（如上部结构型式、后方填土等）进行分析，可发现：上部为框架结构时，桩顶处拉应力值较小，危险截面位于桩-土交界面；码头结构后方有高填土时，后排桩基拉应力较大，码头前沿桩基应力反而较小。在此基础上，对类似结构的设计提出了一些建议。
[Abstract]:High-pile wharf is a common type of wharf structure in port construction in China, which plays an important role in port construction and development. The previous earthquake damage shows that the structure of high pile wharf is easy to be damaged by earthquake, so it is very important to have enough seismic capacity in its design life. In this paper, considering pile-soil interaction and taking random process as the input of ground motion, the characteristics of random seismic response of high pile wharf are analyzed. The main research contents and results are as follows: 1) the commonly used methods of ground motion input and pile-soil contact simulation are summarized, and the relevant parameters are obtained by referring to the code for seismic design of buildings (GB50011-2010) and the previous research results. The large-scale universal finite element software ABAQUS is used as the platform. A two-dimensional finite element model of high pile wharf is established. 2) the structural natural vibration analysis of the finite element model is carried out, the modal modes of the high pile wharf structure are calculated, and the vibration characteristics and the required modal order of the structure are determined. (3) considering the pile-soil interaction, the response spectrum of the high pile wharf structure is analyzed, and the displacement and stress curves of the structure under three different directions of earthquake excitation are obtained. By analyzing the curves obtained, it is found that the wharf structure capsized forward under horizontal earthquake excitation, and the whole wharf structure moves forward horizontally under vertical earthquake excitation, and horizontal excitation plays a leading role in the deformation of soil and structure. 4) the random seismic response of the finite element model of high pile wharf is analyzed, and the power spectrum curves of structural response displacement and tensile stress under random earthquake excitation are obtained. Then, the power spectrum curve of tensile stress response is analyzed, and the root mean square value of tensile stress in the confidence interval with 75% probability is obtained. It can be concluded that the peak value of the relative displacement power spectrum of the terminal node appears at the lower frequency, and the influence of the high-order mode on the structure response is limited. 5) by comparing the results of response spectrum analysis and random seismic response analysis, it can be seen that the variation trend of displacement and stress curves obtained by the two methods is consistent, and the order of magnitude is the same. But there is a difference between them in numerical value, among which, the maximum value of stress obtained by response spectrum analysis is larger. It can be concluded that the response spectrum analysis is relatively conservative, and it is necessary to analyze the power spectrum of engineering examples. 6) by analyzing the influencing factors of seismic response (such as superstructure type, rear fill, etc.) under earthquake action, it is found that when the upper part is frame structure, the tensile stress at the top of pile is small, and the dangerous section is located at the interface between pile and soil; When there is high fill behind the wharf structure, the tensile stress of the back row pile foundation is larger, but the pile foundation stress at the front end of the wharf is smaller. On this basis, some suggestions for the design of similar structures are put forward.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U656.113

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