高桩承台基础桥墩抗震性能研究

发布时间：2018-03-03 19:00

本文选题：高桩承台基础　切入点：试验模型　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：高桩承台基础以其众多优点在桥梁工程中得到了广泛应用。本文结合铁路桥梁桩基础竖向承载力高，，但水平承载力相对较差的特点，采用试验研究与数值分析相结合的方法，系统地研究了铁路桥梁高桩承台基础桥墩的抗震性能和水平荷载作用下桩身应力的分布与变化规律。主要研究工作如下：（1）在查阅大量文献资料的基础上，系统总结了桥梁桩基的震害特点、桩基抗震性能试验研究现状。（2）详细介绍了水平荷载作用下单桩及群桩基础线性及非线性分析的计算理论及计算方法。（3）以石太客运专线上某一具体实桥桥墩为研究对象，在室内建立缩尺比例为1:8的群桩基础桥墩模型，利用拟静力试验得到了在墩顶低周反复荷载作用下，桩土-承台-墩整体结构的力-位移关系滞回曲线和骨架曲线；通过对桩身纵向钢筋应变的量测及分析，得到了水平荷载作用下群桩基础中各排桩桩身应力的分布与变化规律；分析了铁路桥梁高桩承台基础的破坏机理。（4）在试验研究的基础上，分别用日本相关规范推荐的等效非线性土弹簧法模拟土体的弹塑性，分布P-MM塑性铰模拟桩身在变轴力作用下的弹塑性，分布M塑性铰模拟墩的弹塑性，建立了弹塑性梁单元分析模型，并通过模型试验验证了分析模型的合理性。（5）通过对试验模型进行Pushover分析，获得了考虑桩-土-结构相互作用的骨架曲线，该曲线与试验所得骨架曲线吻合较好。基于群桩基础静力非线性分析模型，研究了墩顶水平荷载作用下高桩承台基础中各排桩的桩身轴力、桩身弯矩和桩头负弯矩的分布和变化规律。并在此基础上计算了水平荷载作用下的桩身应力，计算结果显示桩身最大应力点位置与试验结果一致。
[Abstract]:High pile cap foundation has been widely used in bridge engineering because of its many advantages. Considering the characteristics of high vertical bearing capacity but relatively poor horizontal bearing capacity of railway bridge pile foundation, the method of combining experimental research with numerical analysis is adopted in this paper. This paper systematically studies the seismic behavior of the pier of the high pile cap foundation of railway bridge and the distribution and variation of the stress of the pile body under the action of horizontal load. The main research work is as follows:. 1) on the basis of consulting a large number of documents, the characteristics of earthquake damage of bridge pile foundation and the present situation of seismic performance test of bridge pile foundation are systematically summarized. The calculation theory and calculation method of linear and nonlinear analysis of pile and pile group foundation under horizontal load are introduced in detail. Taking a concrete bridge pier on Shi-Tai passenger dedicated line as the research object, the model of pile group foundation pier with scale ratio of 1: 8 is established indoors. By using quasi-static test, under the action of low cyclic cyclic load on the top of the pier, the model is obtained. The hysteretic curve and skeleton curve of the whole structure of pile-soil-pedest-pier, through measuring and analyzing the longitudinal reinforcement strain of pile body, the distribution and variation law of pile body stress in pile group foundation under horizontal load are obtained. The failure mechanism of high pile cap foundation of railway bridge is analyzed. 4) on the basis of experimental study, the equivalent nonlinear soil spring method recommended by relevant codes in Japan is used to simulate the elastoplasticity of soil, the P-MM plastic hinge is used to simulate the elastoplasticity of pile body under variable axial force, and the elastic plasticity of distributed M-plastic hinge to simulate pier. The model of elastic-plastic beam element analysis is established, and the rationality of the model is verified by model test. 5) the skeleton curve considering pile-soil-structure interaction is obtained by Pushover analysis of the test model, which is in good agreement with the experimental skeleton curve. Based on the static nonlinear analysis model of pile group foundation, The distribution and variation law of axial force, bending moment of pile body and negative moment of pile head in pile cap foundation of high pile cap under horizontal load at the top of pier are studied, and the stress of pile body under horizontal load is calculated on the basis of the analysis of the axial force of pile body, the bending moment of pile body and the negative moment of pile head under the action of horizontal load. The calculated results show that the position of the maximum stress point of the pile body is consistent with the test results.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55;U443.22

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