西堠门公铁两用大桥高桩承台基础波流荷载特性研究  

Research on Wave-Current Force Characteristics of Foundation Consisting Long Piles and Pile Cap in Xihoumen Rail-cum-Road Bridge

作　　者：肖海珠 魏凯[1] 胡楷宇[1] 李小珍 XIAO Hai-zhu;WEI Kai;HU Kai-yu;LI Xiao-zhen(Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,China;China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]西南交通大学桥梁工程系,四川成都610031 [2]中铁大桥勘测设计院集团有限公司,湖北武汉430056

出　　处：《桥梁建设》2023年第2期27-35,共9页Bridge Construction

基　　金：国家自然科学基金项目(52222804,51978578)。

摘　　要：西堠门公铁两用大桥主桥5号桥塔采用高桩承台深水基础,承台为六边形截面,长68 m、宽46.4 m、高10 m,桩长88 m。为了解该跨海桥梁高桩承台深水基础在海洋环境下的波流荷载特性,对高桩承台基础在不同波流条件下所受波流力展开研究。采用CFD软件Flow 3D建立三维波流数值水槽模型,实现波流耦合数值仿真,在通过缩尺模型水槽试验验证可靠的基础上,采用数值仿真计算高桩承台基础不同构件在波流同向、反向及纯波时,不同流速条件下所受波流力,并分析群桩波流力的非均匀特性,提出群桩波流力非均匀性系数γ和桩基系数K以表征群桩波流力特性。结果表明:高桩承台基础在纯波及波流同向时横桥向波流力变化不大,在波流反向时横桥向波流力显著增加,其最大值为纯波条件下最大值的1.13倍;承台所受横桥向波流力在波流同向时随流速增大而减小,在波流反向时一定流速范围内随流速增大而增大;群桩主要受水流力作用,所受作用力随流速增大而增大;群桩波流力非均匀性系数γ最大可达75.9%。The pylon No.5 of main bridge of Xihoumen Rail-cum-Road Bridge is supported on a deepwater foundation that is composed of long piles(88 m)and a large pile cap.The pile cap is of a hexagonal cross-section,measuring 68 m long,46.4 m wide and 10 m deep.To investigate the wave-current force characteristics of the deepwater foundation in marine environment,the wave-current forces acting on the foundation in different wave and current conditions are analyzed.A spatial flume model was developed in Flow 3D of CFD software to simulate the wave and current interaction.Upon the verification results of the scaled-down model flume test,the wave-current forces with different flow velocities on various components of the foundation was numerically simulated,when the waves are with currents in the same direction and in the opposite direction,and when there are pure waves.The non-uniformity of the wave-current forces on the pile group is analyzed,the non-uniformity coefficientγand the pile coefficient K are proposed to denote the characteristics of wave-current force on pile group.It is shown that there is slight fluctuation of transverse wave-current forces on the elevated pile cap under the action pure waves and waves with currents in the same direction.While when the waves are with currents in the opposite directions,the transverse wave-current forces are significantly increased,with a maximum value reaching 1.13 times of the maximum value under pure waves.The transverse wave-current forces on the pile cap go down as the flow velocity reduces when the waves are with currents in the same direction,while go up as the flow velocity increases in a specific range when the waves are with currents in the opposite direction.The group piles are mainly subjected to wave-current forces,and the wave-current forces increase as flow velocity rises.The non-uniformity coefficientγof the wave-current forces on group piles can reach a maximum value of 75.9%.

关 键 词：跨海桥梁 高桩承台基础 波流作用 荷载特性 波流力 水槽试验 数值模拟 

分 类 号：U443.1[建筑科学—桥梁与隧道工程] U441.2[交通运输工程—道路与铁道工程]