信江八字嘴枢纽坝下冲刷计算研究
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摘要
针对枢纽下游河床冲刷这一水利航运界普遍关注的工程问题,为确保信江八字嘴航电枢纽工程的安全及下游通航条件,基于信江水文基本特性、河床演变特性分析,建立平面二维水沙数学模型,对八字嘴枢纽建成运行后可能引起的坝下冲刷进行了计算研究。结果表明:工程河段地处鄱阳湖影响范围,天然情况下洲滩小幅淤长,河道演变较为稳定,但近年来部分区域频繁的采砂活动造成局部河床显著下切,需要引起高度重视;经过10个水文年冲淤调整后,西大河坝下5 km范围内因大规模采砂作用河床深凹、水深较大,故冲刷幅度相对不大;坝下5～10 km范围冲刷较为明显,冲刷部位主要在河槽,平均冲刷深度约为0. 29～0. 93 m,边滩部分变化很小;东大河由于下游双港枢纽的抬水作用,坝下冲刷幅度整体较小。总体来看,八字嘴枢纽坝下河床冲淤变化的幅度随时间逐渐减小,河道河势基本保持稳定。
The scour of the downstream river bed is an engineering problem of wide concern in the water conservancy and shipping fields. In order to ensure the safety and the downstream navigation conditions of the Bazizui Navigation and Hydropower Project of Xinjiang River,a 2-D water-sediment mathematical model is established herein on the basis of the analysis on both the basic hydrological characteristics of Xinjiang River and the evolution feature of its bed,and then the possible downstream scour of the dam for the project to be caused after the complete of Bazizui Project is calculated. The result shows that the engineering section is located in the influence area of Poyang Lake,and the river channel evolves stably with small siltation of the beach under natural conditions. In recent years,frequently sand mining activities in some areas caused the significant downward cutting of the local river bed,which needs to be paid great attention. After 10 hydrological years,the scour range is relatively small in the river bed of 5 km under West River Dam,since the large-scale sand mining activities caused the river bed is concave with deep water level. The scour is more obvious within the range of 5 ～ 10 km of the downstream river reach of the project,while the scoured locations are mainly concentrated inside the river channel,for which the mean scouring depth is to be 0. 29 ～ 0. 93 m and the variations of both the side shoals are less. The scour range under the East River Dam is small because of the water lifting effect of the Shuanggang Project of the downstream. As a whole,the amplitude of the scouring and silting evolution of the river bed of the downstream is to be gradually decreased with the time,thus the river regime is to basically remain stable.
The scour of the downstream river bed is an engineering problem of wide concern in the water conservancy and shipping fields. In order to ensure the safety and the downstream navigation conditions of the Bazizui Navigation and Hydropower Project of Xinjiang River,a 2-D water-sediment mathematical model is established herein on the basis of the analysis on both the basic hydrological characteristics of Xinjiang River and the evolution feature of its bed,and then the possible downstream scour of the dam for the project to be caused after the complete of Bazizui Project is calculated. The result shows that the engineering section is located in the influence area of Poyang Lake,and the river channel evolves stably with small siltation of the beach under natural conditions. In recent years,frequently sand mining activities in some areas caused the significant downward cutting of the local river bed,which needs to be paid great attention. After 10 hydrological years,the scour range is relatively small in the river bed of 5 km under West River Dam,since the large-scale sand mining activities caused the river bed is concave with deep water level. The scour is more obvious within the range of 5 ～ 10 km of the downstream river reach of the project,while the scoured locations are mainly concentrated inside the river channel,for which the mean scouring depth is to be 0. 29 ～ 0. 93 m and the variations of both the side shoals are less. The scour range under the East River Dam is small because of the water lifting effect of the Shuanggang Project of the downstream. As a whole,the amplitude of the scouring and silting evolution of the river bed of the downstream is to be gradually decreased with the time,thus the river regime is to basically remain stable.
引文
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[14]徐十锋,陈界仁.新干枢纽下游河床冲淤及航道条件变化计算[J].水运工程,2015(7):124-128.
[15]夏莉敏,张玮,雷雪婷.长洲枢纽下游近坝段河道考虑河床粗化的冲刷模拟研究[J].水运工程,2009(12):148-153.
[2]韩其为,杨小庆.我国水库泥沙淤积研究综述[J].中国水利水电科学研究院学报,2003,1(3):169-178.
[3]张燕菁,胡春宏,王延贵.国外典型水利枢纽下游河道冲淤演变特点[J].人民长江,2010,41(24):76-80.
[4] XIA J Q,ZONG Q L,ZHANG Y,et al. Prediction of recent bank retreat processes at typical sections in the Jingjiang Reach[J].Science China(technological sciences),2014,57(8):1490-1499.
[5]张炯,陈立,何娟,等.三峡水库蓄水后宜都水道演变及航道变化[J].水运工程,2006(8):83-86.
[6]陈立,张俊勇,谢葆玲.河流再造床过程中河型变化的实验研究[J].水利学报,2003,34(7):42-45.
[7]乐培九,程小兵,王艳华,等.枢纽下游河床冲刷深度和水位降落估算方法[J].泥沙研究,2012,37(3):57-63.
[8]刘达.清远水利枢纽坝下河床冲刷及其对下引航道的影响研究[J].黑龙江水利科技,2012,40(7):200-201.
[9]庞雪松,杜敬民,假冬冬,等.西江长洲枢纽下游近坝段水位下降特征及调控措施[J].水利水运工程学报,2014(3):42-48.
[10]张柏英,李一兵.枢纽下游河床极限冲刷及水位降落研究进展[J].水道港口,2009,30(2):101-107.
[11]谢作涛,侯卫国,任昊.葛洲坝下游宜昌一杨家脑河段平面二维水沙数学模型[J].水科学进展,2008,19(3):309-316.
[12]朱铁蓉,杨芳丽,白洋,等.汉江崔家营水库修建后坝下游河床冲刷预测[J].中国农村水利水电,2009(1):8-10.
[13]万占伟,安催花,闫朝晖.小浪底水库对下游河道的冲刷效果及趋势预测[J].人民黄河,2012,34(5):6-8.
[14]徐十锋,陈界仁.新干枢纽下游河床冲淤及航道条件变化计算[J].水运工程,2015(7):124-128.
[15]夏莉敏,张玮,雷雪婷.长洲枢纽下游近坝段河道考虑河床粗化的冲刷模拟研究[J].水运工程,2009(12):148-153.