规则波浪作用下对称八边形沉井受力数值模拟研究  

Numerical Study of Regular Wave Forces on Symmetrical Octagonal Caisson

作　　者：韩嘉怡 卢宝洁 祝兵[1] HAN Jia-yi;LU Bao-jie;ZHU Bing(Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学桥梁工程系,四川成都610031

出　　处：《桥梁建设》2023年第1期94-100,共7页Bridge Construction

基　　金：国家自然科学基金项目(52278221,U1834207)。

摘　　要：为研究对称八边形沉井结构较传统沉井结构对周围流场遮蔽效应与受力激增的改善作用,采用数值模拟方法进行沉井结构受力特性分析。基于RNGκ-ε湍流模型及RANS方程,采用Flow3d软件建立水槽三维数值模型,在验证数值模型有效性的基础上,分析对称八边形、圆端形和矩形沉井结构在入射角为0°、30°、45°、60°、90°的规则波浪作用下,各结构周围流场的流速分布特性与波浪力,并与《港口与航道水文规范》(JTS 145—2015)的计算结果对比。结果表明:对称八边形沉井结构可有效改善传统沉井结构对周围流场的遮蔽效应与受力,使结构周围流场流速分布更均匀;与入射角为0°相比,入射角为30°~60°时,对称八边形、圆端形、矩形沉井结构所受的最大总水平波浪力激增1.5~1.8倍,建议在实际工程设计中考虑入射角的影响;入射角为90°时,规范计算的矩形沉井结构波浪力低于数值模型计算的对称八边形沉井结构波浪力。入射角为0°~90°时,规范计算的圆端形沉井结构波浪力均高于数值模型计算的对称八边形沉井结构,建议采用圆端形沉井结构计算方法指导对称八边形沉井结构设计。In this paper,the mechanical properties of the symmetrical octagonal caisson are numerically simulated to examine if the octagonal caisson,compared with the round-cornered and rectangular caissons,has better shielding effect and stronger resistance to force surge in the surrounding flow fields under regular wave forces.Based on the RNGκ-εturbulence model and RANS equations,a 3D numerical flume model was developed with FLOW-3D.The simulated results were compared with the literature results,to verify the effectiveness of the numerical model.The velocity distribution characteristics and wave forces around the octagonal,round-cornered and rectangular caisson structures were analyzed under regular wave forces and when the wave incidence angles were at 0°,30°,45°,60°and 90°,respectively,and the findings were judged with the suggestions in the Code of Hydrology for Harbor and Waterway(JTS 145-2015).It is shown that the symmetrical octagonal caisson has better shielding effect and load bearing capacity,around which,the flow fields and velocity show more uniform distribution.When the wave incidence angles are between 30°and 60°,the maximum horizontal forces on the caisson structures(round-cornered,rectangular and symmetrical octagonal)are intensified 1.5 to 1.8 times,compared with the situations at the wave incidence angle of 0°,and the influence of wave incidence angle should be considered in the real engineering design.With a wave incidence angle of 90°,the theoretical wave forces on the rectangular caisson are lower than the simulated wave forces on the symmetrical octagonal caisson.When the wave incidence angles are between 0°and 90°,the theoretical wave forces on the round-cornered caisson are higher than the simulated wave forces on the symmetrical octagonal caisson,it is suggested that the calculation methods of round-cornered caisson be used for load bearing capacity calculation and structural design of symmetrical octagonal caisson.

关 键 词：桥梁工程 沉井基础 规则波浪 对称八边形结构 圆端形结构 矩形结构 受力特性 数值模拟 

分 类 号：U443.131[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]