摘要
大型调水工程通常采用深水明渠输送,受供水保证率制约,渠道边坡衬砌板的修复通常只能在不停水条件下进行。内静外动钢围堰目前采用的是一种新的深水渠道水下施工技术。为评估施工对渠道输水的影响,对钢围堰绕流水力特性开展研究十分必要。通过采用三维水动力数值模拟与概化物理模型验证相结合的方法,对比分析了钢围堰渠段的水深场和流速分布的空间变化。研究表明钢围堰绕流影响了上下游渠道的流态,形成约0.11 m的局部水头损失;上游壅水长度约40 m,平均壅高约0.15 m;缩窄段局部水面跌落,流速增大为上游来流的1.58倍;下游扩散段有回流区,造成湍动能集中耗散,同时卷吸作用则对截留施工漂浮物有利。虽然钢围堰渠段的水流结构历经收缩与扩散的调整,但过流总体比较适顺,对渠道过流能力影响较小;研究成果可以为深水明渠护坡的不停水维修施工提供技术支撑。
Large-scale water transfer projects usually use deep-water open channels for transportation.Due to the limitation of the water supply guarantee rate,the repair of the slope lining board can usually only be carried out under the condition of continuous water supply.The current internal static and external dynamic steel cofferdam is a new underwater construction technology for deep-water channels.In order to evaluate the impact of construction on the channel water delivery,it is necessary to carry out research on the hydraulic characteristics of the steel cofferdam.By using the method of combining three-dimensional hydrodynamic numerical simulation and generalized physical model verification,the spatial variation of the water depth field and velocity distribution of the steel cofferdam canal section is compared and analyzed.Studies show that the flow around the steel cofferdam affects the flow patterns of the upstream and downstream channels,resulting in a local head loss of about 0.11 m;the upstream backwater length is about 40 m,and the average backwater height is about 0.15 m;the local water surface of the narrowing section drops,and the flow velocity increases to the upstream flow is 1.58 times.The downstream diffusion section has a back flow zone,which causes the turbulent kinetic energy to be dissipated centrally.At the same time,the entrainment effect is beneficial to intercepting construction floating debris.Although the water flow structure of the steel cofferdam canal section has undergone adjustments of contraction and diffusion,the overall flow is relatively smooth and has little effect on the flow capacity of the channel.The research results can provide technical support for the continuous water maintenance of the deep-water open channel slope protection.
作者
范聪喆
刘明潇
甄映红
武娟娟
孙东坡
FAN Cong-zhe;LIU Ming-xiao;ZHEN Ying-hong;WU Juan-juan;SUN Dong-po(Institute of Hydraulics and Rivers,North China University of Water Resources and Electric Power,Zhengzhou 450046,Henan Province,China;School of Architectural Engineering,Institute of Hydraulics and Rivers,Kaili University,Kaili 556011,Guizhou Province,China)
出处
《中国农村水利水电》
北大核心
2021年第5期139-144,共6页
China Rural Water and Hydropower
基金
国家自然科学基金项目(51909093)
华北水利水电大学高层次人才科研启动基金(201904004)。
关键词
深水明渠
钢围堰
绕流
数值模拟
水力特性
open channels of deep water
steel fence
detour flow
numerical modeling
hydraulic characteristics
