转体施工桥梁桩基内力的非均匀性及调控  

Non⁃Uniformity and Control of Internal Forces in Pile Foundation of Rotating Construction Bridges

作　　者：张广潮 李前名 龙俊贤 杨奇志 ZHANG Guangchao;LI Qianmin;LONG Junxian;YANG Qizhi(China Railway Major Bridge Reconnaissance&Design Institute Co.Ltd.,Wuhan 430074,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司,武汉430074

出　　处：《铁道建筑》2024年第10期65-69,共5页Railway Engineering

基　　金：国家自然科学基金(52178451,52278231,U1434204)。

摘　　要：为研究转体工况下桥梁承台处于单点受力模式时群桩桩基内力分配非均匀性及其影响因素,本文以跨襄北编组站转体施工斜拉桥为例,建立弹性支撑拉压杆模型计算桩基反力,分析承台厚度对桩基内力分配非均匀性的影响。建立承台-桩基有限元模型计算转体工况下桩基内力及分布规律,并与实测结果进行对比,研究柔性承台施加预应力对桩基内力分配的影响。结果表明:承台相对刚度系数大于4时,满足刚性承台要求,群桩内力相对均匀分布;当承台相对刚度系数小于等于4时,为半刚性或柔性承台,群桩内力表现为中心桩大于四周桩的非均匀性,且相对刚度系数越小,非均匀性越显著;对半刚性及柔性承台合理施加纵横向预应力,能够有效改善群桩内力分配不均匀性的问题。In order to study the non-uniformity of internal force distribution in the pile group foundation and its influencing factors when the cap is in a single-point stress mode under the rotating condition of the bridge,taking a large-tonnage rotating construction cable-stayed bridge as an engineering example,the pile foundation reaction with the help of the elastically braced strut-and-tie model was calculated in this paper,and the influence of different thickness of the cap on the non-uniformity of internal force distribution of the pile foundation was analyzed.A finite element model of the cap-pile foundation was established to calculate the internal forces and distribution of the pile foundation under rotational conditions,and compared with the measured results to study the effect of applying prestress to the flexible cap on the internal force distribution of the pile foundation.The results show that when the relative stiffness coefficient of the cap is greater than 4,it meets the requirements of a rigid pier and the internal forces of the pile group are relatively evenly distributed.When the relative stiffness coefficient of the cap is less than or equal to 4,it is a semi-rigid or flexible bearing platform,and the internal forces of the pile group exhibit non-uniformity where the central pile is greater than the surrounding piles,and the smaller the relative stiffness coefficient,the more significant the non-uniformity.Reasonably applying longitudinal and transverse prestress to semi-rigid and flexible caps can effectively improve the problem of uneven distribution of internal forces in pile groups.

关 键 词：转体承台 空间拉压杆模型 理论计算 数值模拟 群桩基础 预应力 内力非均匀性 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]