大跨混凝土拱桥基础形式设计及结构验算方法探讨

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发布时间：2021-09-09

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大跨混凝土拱桥基础形式设计及结构验算方法探讨
南
(中铁二院工程集团有限责任公司，成都610031)
摘要：某370 m跨上承式混凝土拱桥为一无铰拱桥，基础形式设计以及结构验算方法影响到结构整体受力
性能和安全性。文章介绍了该桥总体布置、施工方法以及桥位地质地形特征，在此基础上推出了3种基础形
式方案，阐述了各方案的特点以及平立面布置。在综合比较工程量、工程复杂度以及工程风险的基础上推荐
了嵌岩基础形式，并阐明其优缺点。文章还列举了现有设计规范手册中的嵌岩基础的结构验算方法，比较了
2种嵌岩深度的计算方法，提出考虑拱脚剪力的计算方法偏于安全。文章还强调嵌岩深度基础除了深度外还
必须验算轴力以及自身截面强度并给出计算要点。
关键词：混凝土拱桥；基础设计；嵌岩基础
中图分类号：U24 文献标志码：A
Discussion on Foundation Form Design and Structure Checking M ethod
of Long Span Concrete Arch Bridge
YAO Nan
(China Railway Eryuan Engineering Group Co．，Ltd．，Chendu 610031，China)
Abstract：A deck concrete arch bridge with a span of 370 m is a hingeless arch bridge，its foundation form design and
structure computation methods will effect the structural behavior and safety of the bridge．In this paper，general layout，
construction methods and geological characteristics of the bridge site are introduced firstly and three foundation form
schemes are proposed for comparison with their characters，plane and facade layouts．Rock—socketed foundation is rec—
ommended with its advantages and disadvantages set forth based on a comprehensive comparison of engineering quantity，
engineering complexity and engineering risk．Subsequently checking computation methods of the rock-socketed founda—
tion in current codes and handbooks are listed．Two rock-socketed depth computation methods are compared，and one
with consideration of arch springing shearing force is considered safer． At last，checking computations of axial force and
section strength are emphasized in the paper besides depth checking，and calculated main points shall be given．
Key words：concrete arch bridge；foundation design；rock—socketed foundation
1 工程概况
某上承式混凝土拱桥为一双线铁路无铰拱桥，横
跨某山涧深谷，其跨度设置为370 m，矢跨比为
1／4．512，桥面宽度为12．6 m。图1为该桥总体布置
图。其中拱轴曲线采用拱轴系数m=5的悬链线。
4×3 800 3×3 800 4× 3 800
拱圈结构采用分岔的提篮拱形式，2片拱肋内倾角为