【作者】 郑斐；

【导师】 贺拴海；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2014， 博士

【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。更多还原

【Abstract】 This dissertation is in the background of the sub-topic Pier Form Comparison andStability Research of Mountionous Bridges, which is one of the R&D projects taken byCCCG The Key Technologies of Resource-saving Research in Mountainous HighwayConstruction. The high pier stability analysis and horizontal displacement theory is mainlyused to seek the sensitivity parameters and their regular pattern of impact on high pier stability.Taking the influence of foundation on the high pier stability into consideration, by the meansof horizontal displacement calculation method, and relying on the data collected by innermodel test and monitoring at the project site, the method of the stability analysis, piercalculated length and horizontal displacement calculations is verified.Based on the domestic and foreign presdent situation and development of stabilityanalysis theory and horizontal displacement calculation method on bridges, the calculation ofstability calculation and horizontal displacements in the high pier bridge has importantsignificance. Especially the length factor has great impact on increasing eccentricitycoefficient. Compared with British and American norms, the existing bridge specification inChina is not only sketchy, and the value of the safety factor is not included. Designers oftenuse their experience to calculate, so that it is easily to be radical or conservative in designinghigh pier; while pier top horizontal displacement calculations have big differences among thevarious calculation methods.This paper reviews the development and research statust of the pier stability, horizontaldisplacement and the pier type on selected bridges, and sort out different types and cablesystem bridge combed on12kinds of pylon pier bridges. Investigation of the practicalapplication of high bridge pier6highway completed in recent years in our country is taken,and based on a statistical analysis of817samples of high pier213bridges, summarize thesuitable height interval of4common pier type.In this paper, energy method is used to derive the solving the equation of high pierconstruction stage and operation stage of the pier top weight concentrated vertical loads ofcritical buckling load. Through four types of pier type in different parameters, different heightof pier under the conditions of the stability analysis, the pier one order stability coefficient in50to60meters range decreases quickly, the height between60tand90meters is in flat region.The pier under the action of a concentrated load, the same height distribution under different pier stability coefficient size is dispersing; thin-walled hollow pier stability coefficient ishigher than other three kinds of pier type, especially between the60and90meters. Based onthe project, two kinds of stability analysis is taken and results showes that considering twokinds of nonlinear effects, the calculation results are lower than the values, the linear stabilityanalysis result is not conservative, the ultimate bearing capacity is limit; nonlinear stabilityanalysis of the steady line number is greater than1.58, which meets the safety requirements;and the number of beams in double column pier in-plane stability is monotone increasing.This paper studies that under different boundary conditions, calculated length of highpier methods are put forward under different conditions of high pier calculation lengthcoefficient. Considering the geometric nonlinear pier, pier under different boundaryconditionsare derived first order calculation equation for destabilization critical force, usingEuler formulacalculation length coefficient. Under the elastic foundation, pier pier conditionscalculated length andstandard deviation is0.65%; under the bridge into a rigid foundationpiers calculatedlength and standard deviation is less than1%; elastic foundation pier bridgestatecalculation length and standard length, deviation is less than0.5%, and this formula isverified.The shape function is given in this paper, a method to calculate the horizontaldisplacement of high pier is set up. Based on the principle of potential energy, thedisplacement of pier top are analyzed. Different boundary conditions of high pierdeformation,a method to calculate the horizontal displacement of high pier is also given.According to the given different mechanical models of boundary conditions of the pier shape,fThe method is derived for elastic constraint conditions, no formula for calculating the piertopconstraints under various conditions such as the horizontal displacement of the top of pier.And on the basis of rigid foundation,a practical formula for calculating the horizontaldisplacement of high pier is proposed for a constraint pier on the top.The research achievements not only provide technical support to determine thereasonable range, high pier bridge form and stress state in the stage of bridge designing, butalso provide the basis for the revision of the relevant sections for specification.更多还原