考虑地基影响的高桥墩稳定及水平位移实用计算方法

发布时间：2018-01-18 07:00

本文关键词：考虑地基影响的高桥墩稳定及水平位移实用计算方法　出处：《长安大学》2014年博士论文　论文类型：学位论文

【摘要】：本学位论文以中交集团特大科技研发项目《山岭区资源节约型高速公路建设关键技术研究》的子课题《山区桥梁高墩形式比选及稳定性研究》为背景，，旨在通过高桥墩稳定性分析及水平位移理论方法，寻求影响高桥墩稳定性的敏感性参数及内在规律，建立考虑地基影响的高桥墩稳定及水平位移实用计算方法；并以有限元分析、室内模型试验研究和依托工程现场监测为手段，验证分析高墩稳定性、计算长度和墩顶水平位移的计算方法。本文指出稳定计算和水平位移计算问题在高墩桥梁设计中具有重要意义，特别是在计算长度系数对偏心距增大系数影响较大，而我国现行桥梁规范有关条文相比英、美规范较为粗略，且取值未包含“偏保守采用值”。同时，墩顶水平位移的计算至今在多种计算方法之间还存在较大出入。本文回顾了桥墩稳定、水平位移和墩型比选的发展及研究现状，梳理了桥墩的分类形式，介绍了多种桥型中桥墩或桥塔的基本情况。调研了我国近年建成的6条不同地域山区高速公路中高桥墩的应用情况，统计分析了213座桥梁中817个高墩样本，总结了4种较常见桥墩墩型的适用高度区间。本文基于能量原理，推导了高桥墩在施工阶段自重以及运营阶段墩顶集中竖向荷载作用下临界稳定荷载的近似求解公式。分析了四种桥墩在不同截面参数、不同墩高条件下的稳定性，结果显示各墩型一阶稳定安全系数50～60米范围内降低较快，60～90米降幅区域平缓；薄壁空心墩稳定安全系数明显高于其他三类墩型，尤其是在60～90米区间范围内其稳定性优势明显。基于有限元法，对依托工程进行了两类稳定分析，结果显示：考虑二类非线性影响时，计算结果都比特征值低，说明线性稳定分析求得的结果不保守，是极限承载力的上限；非线性稳定分析结果得到的稳定安全系数均大于1.58，满足稳定安全要求；系梁设置数量对算例中双柱式墩的面内稳定并非呈单调增长。本文研究了不同边界约束条件下高墩的计算长度，提出了不同状态下高墩计算长度系数的计算方法。考虑桥墩的几何非线性，推导了桥墩不同边界条件下一阶失稳临界力的计算公式，并利用欧拉公式得到其计算长度系数。其中，本文公式在弹性地基裸墩施工阶段、成桥运营阶段刚性地基状况下、成桥运营阶段弹性地基状况下计算值与规范规范规定值相比，偏差均小于1%。本文给出了不同边界约束条件下高墩受力变形的形函数，基于势能驻值原理，针对墩顶位移进行了分析。针对给出的墩身形函数，研究了地基弹性约束条件、无墩顶约束等不同条件下墩顶水平位移的计算公式，并在该基础上，给出了刚性基础有墩顶约束时，计算高墩墩顶水平位移的实用公式。本文研究成果不但可在桥梁设计阶段，为确定合理桥高范围、桥墩形式以及受力状态提供技术支持，还可为下一步规范有关条款的修订工作提供依据。
[Abstract]:High pier form sub project of < mountain bridge in this thesis cccg large science and technology research and development project "construction in mountain area highway resource conservation research on key technology selection and stability of > > as the background, through the analysis of high pier stability and horizontal displacement theory, seeking to influence the stability of the high pier of the sensitive parameters and intrinsic rules a calculation method of high pier stability and horizontal displacement of foundation is considered practical effect; and the finite element analysis, indoor model test and on-site monitoring as a means of verification and analysis of high pier stability, calculation method of length and lateral displacement of pier.
This paper points out that the horizontal displacement calculation and stability calculation has important significance in the design of high pier bridge, especially in the calculation of the length coefficient on the coefficient of eccentricity is greatly affected, and our current bridge code provisions compared with British and American code is more rough, and the value is not included "conservative use value". At the same time, the larger the entry between pier top horizontal displacement has been in a variety of calculation methods.
This paper reviews the pier stability, horizontal displacement and pier type selection of research and development, combing the classification form of bridge piers, introduced the basic situation of bridge types of bridge pier or tower. Investigation of the high pier 6 different regional highway built in China in recent years, the application of statistical analysis, 817 a sample of 213 high pier bridges, summarizes the suitable height interval of 4 common pier type.
Based on the energy principle, deduces the approximate solution formula in high pier construction stage and operation stage of gravity pier top concentrated vertical load critical load. Analyze four piers in different parameters, the stability of different pier conditions. The results showed that each pier one order stability safety factor of 50 to 60 meters range in 60 ~ 90 meters decreased rapidly, fell flat region; the safety factor of stability of the thin-walled hollow pier is significantly higher than the other three types of piers, especially in the 60 to 90 meters range stability advantages. Based on the finite element method, based on the project of the two stability analysis, results showed that: considering two kinds of nonlinear effects when the calculation results are lower than the values, that the linear stability analysis result is not conservative, the ultimate bearing capacity of the upper limit; nonlinear stability analysis of the stability safety coefficients were greater than 1. 58, the stability and safety requirements are met, and the number of beam setting is not monotonous growth for the internal stability of the double column piers in the example.
This paper studies the different boundary conditions to calculate the length of the high pier, put forward a calculation method under different conditions of high pier calculation length coefficient. Considering the geometric nonlinearity of the pier, the pier is deduced under different boundary conditions of first order loss calculation formula of the critical buckling force, and the use of the Euler formula calculated length coefficient. Among them, the the formula in the stage of elastic foundation pier construction, bridge rigid foundation conditions, the operational phase of the bridge elastic foundation condition calculation value and standard deviation is less than the specified value compared to 1%.
The shape function is given in this paper. The different boundary condition of high pier deformation, based on the principle of minimum potential energy, the displacement of pier top are analyzed. Aiming at the pier shape function is given, the elastic constraints, no constraint on the top calculation formulas under different conditions of pier top displacement, and in based on this, given a rigid foundation pier top constraint, a practical formula for calculation of high pier top horizontal displacement.
The research results in this paper can not only provide technical support for determining the reasonable height of bridge, the form of pier and the state of stress in the bridge design stage, but also provide a basis for further revision of relevant clauses.

【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U443.22

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