水流作用下桩基局部水沙动力特征数值模拟  

Numerical simulation of local hydro-sediment dynamics around pile foundations under flow conditions

作　　者：伍志元[1,2] 李昂 蒋昌波[1,2,3] 高凯[1] 陈杰 邓斌[1,2] WU Zhiyuan;LI Ang;JIANG Changbo;GAO Kai;CHEN Jie;DENG Bin(School of Hydraulic and Environmental Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China;School of Civil Engineering,Hunan University of Technology,Zhuzhou 412007,China)

机构地区：[1]长沙理工大学水利与环境工程学院,湖南长沙410114 [2]水沙科学与水灾害防治湖南省重点实验室,湖南长沙410114 [3]湖南工业大学土木工程学院,湖南株洲412007

出　　处：《水利水运工程学报》2024年第5期42-53,共12页Hydro-Science and Engineering

基　　金：国家重点研发计划项目(2021YFB2601100);国家自然科学基金面上项目(52171246);湖南省科技计划项目(2023RC3136);湖南省自然科学基金优秀青年基金项目(2022JJ20041)。

摘　　要：基于VOF方法追踪水气界面,利用不可压缩流体连续方程和运动方程对流体进行描述,通过嵌套网格技术建立三维数值水槽,湍流采用RNG k–ε模型,泥沙运动基于Van Rijn方法。基于验证后的数值水槽模型,开展水流作用下高桩承台结构局部水动力和冲刷规律研究,讨论不同来流条件下桩基桩周流场分布、泥沙输运和床面局部冲刷特征。结果表明,桩基冲刷特征受冲刷时间、流速、水位、水流攻角等来流条件的影响,同时也受桩间距的影响。当流速较小时,高桩承台桩基各桩之间相互作用较小,泥沙冲淤形态彼此独立,与单桩冲刷特征相似。流速较大时,前桩对后桩出现较为明显的遮蔽作用,前桩水流涡旋影响后桩,后桩周围流速明显降低,此时泥沙冲刷坑彼此相连构成群桩整体冲刷坑,且在最后排桩桩间形成条状冲刷坑,冲刷深度最大。The Volume of Fluid(VOF)method was employed to track the water-air interface,and the fluid was described using the incompressible fluid continuity equation and motion equations.A three-dimensional numerical flume was established using nested grid technology,with turbulence modeled through the RNG k–εmodel,while sediment transport was based on the Van Rijn method.Using the validated numerical flume model,this study investigates the local hydrodynamic and scouring behavior of pile foundations with pile cap structures under varying flow conditions.The distribution of flow fields around the pile,sediment transport,and local scour characteristics of the bed surface were analyzed.The results indicate that scour behavior is influenced by factors such as scouring duration,flow velocity,water level,flow angle,and pile spacing.At lower flow velocities,the interactions between individual piles in a pile group are minimal,and the sediment erosion and deposition patterns are similar to those of a single pile.However,at higher flow velocities,the upstream piles significantly shield the downstream piles,with vortex shedding from the upstream piles affecting the flow around the downstream piles,resulting in reduced flow velocities.This leads to the formation of a group scour pit,where the scours around individual piles coalesce,and elongated scour pits develop between the last row of piles,reaching the greatest scour depth.

关 键 词：桩基结构 高桩承台 局部冲刷 水沙动力 

分 类 号：TV148[水利工程—水力学及河流动力学]