淤地坝泥沙淤积高度对宽顶堰水力特性的影响  

Influence of siltation thickness on the hydraulic characteristics of the broad crested weir of check dams

作　　者：张家璇 李永业[1] 宋晓腾 陶思远 ZHANG Jiaxuan;LI Yongye;SONG Xiaoteng;TAO Siyuan(College of Water Resource Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学水利科学与工程学院,太原030024

出　　处：《农业工程学报》2023年第13期105-112,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(No.51179116);山西省水利科学技术研究与推广项目(2022GM032)。

摘　　要：为解决淤地坝长期运行,泥沙不断沉积超出设计库容,漫延至溢洪道内并在宽顶堰前堆积从而影响泄流的问题,该研究通过物理模型试验的方法,对不同淤积高度下溢洪道内宽顶堰的水流流态、水面线、流速分布、流量系数等特性进行对比分析。结果表明,随着淤积高度的增加,堰流在保持宽顶堰原有的过流形态同时壅水程度逐渐降低;淤积高度的不同会影响堰前及堰上区域的水面高程和断面流速,堰前水位随着淤积高度的增加略微下降,过流断面逐渐减小,水流流速增大;随着淤积高度的增加,流量系数逐渐增大,即宽顶堰的泄流能力有所增强。因此引入参数相对淤积高度(淤积高度S与堰高P之比),根据试验数据拟合得到了淤积工况下宽顶堰流量系数经验公式,计算流量与实测流量的平均相对误差为2.7%,满足精度要求,可为淤地坝除险加固工程的相关工作提供参考。Check dams are widely located in the Loess Plateau area of western China.Their siltation elevation can exceed the design value after long-term running.The excess sediment spreads into the spillway,and then accumulates in front of the overflow weir,leading to the normal flood discharge.This study aims to clarify the influence of siltation thickness on the hydraulic characteristics of the broad-crested weir of check dams.The spillway of a typical check dam was also selected as the research object.The physical model test was finally carried out to analyze the flow pattern,water surface profile,velocity distribution,and discharge coefficient of overflow weir under different siltation heights.The test results were as follows:the upstream water surface of the broad crested weir was straight and flat under the condition of free flow.Then,the water level was dropped near the weir wall and gradually flattened just above the weir crest.Finally,the flow was fallen from the weir to the downstream channel.Sedimentation in front of the weir was reduced the degree of backwater,and thus the water depth dropped significantly.The overall water surface basically remained the same as that without sediment,and then gradually developed towards the open channel flow,with the increase of siltation thickness.More outstanding behavior was also found under small flow or low hydraulic head.The influence of siltation on the weir flow was further quantified using water surface profile.Therefore,the slight decrease was observed on the water surface line in front of and above the weir crest under different cases with the increase of sedimentation height,compared with the water depth along the weir.The water depth in the area behind the weir was depended mainly on the downstream channel,indicating no influence from the siltation height.Furthermore,there was an increase in the flow velocity in front of and behind the weir increases,where the reduced water level indicated the reduction of the cross-section area.Consequently,the rising siltation el

关 键 词：水力特性 流量 淤地坝 宽顶堰 泥沙淤积 流量系数 

分 类 号：TV651.1[水利工程—水利水电工程]