摘要
水沙条件和水库调度方式是影响三峡工程变动回水区河床演变的重要因素。长江上游正在建设的大型梯级水库群将改变三峡工程变动回水区的来水来沙条件,从而引起泥沙冲淤的变化。本文建立了三峡工程变动回水区洛碛-王家滩河段二维水沙数学模型,模拟了不同水沙条件下该河段的演变趋势。采用三峡蓄水运用后2007-2008年实测资料进行了验证,较好地模拟了天然情况下的涨水淤积过程和受三峡回水影响的累积淤积过程。采用90系列、90+上游建库水沙系列计算了洛碛-王家滩30年后的淤积量及淤积部位。计算表明,受三峡工程变动回水的影响,洛碛-王家滩河段发生累积性淤积。90+上游建库系列淤积量相当于90系列的31.8%～82.3%,主要与长江上游梯级水库拦沙有关。淤积部位主要位于岸线凹凸不平的弯沱、回流区及河道的宽浅河段,淤积后的河床岸线更趋平顺。在此基础上分析了泥沙淤积对重点浅滩上、下洛碛航道的影响。
Water and sediment conditions, as well as the reservoir regulation mode, are important factors which influence the fluctuating backwater area of the Three Gorges Project （TGP）. Water-sediment conditions will be changed by the cascade reservoir group in the Upper Yangtze River under construction, which will cause changes of deposition and erosion in the fluctuating backwater area of the TGP. In this paper, a 2D flow-sediment mathematical model for the fluctuating backwater area from Luoqi to Wangjiatan reach is devel- oped to analyze its evolution tendency in different water and sediment conditions. The measured data, from 2007 to 2008 after impoundment of the TGP, are used to verify the mathematical model. Deposition and ero- sion agree well with the measured data, such as cumulative deposition caused by drawn backwater, deposition caused by rising pool level and erosion caused by drawn down of pool level. Then, the rules of the spatial-tem- poral changes of the sediment deposition and erosion in the Luoqi to Wangjiatan reach in the following 30 years are predicted by the model, under adjusted water-sediment conditions of 1990s and with the upstream reser- voirs. The results show that cumulative deposition happens, influenced by the backwater of the TGP. Deposi- tion occurrs mainly in the river sinuses, the reeirculating zones and broad-shallow reaches. After adjustment by upstream reservoirs, the sediment deposition volume is 31.8% -82.3% of that in 1990s. Then its effects on the harbors and navigation channels are analyzed.
出处
《泥沙研究》
CSCD
北大核心
2013年第2期52-59,共8页
Journal of Sediment Research
基金
国家973计划资助项目(2012CB417002)
"十二五"国家科技支撑计划(2012BAB04B03)
长江三峡工程"十一五"泥沙研究(115-04)
关键词
变动回水区
三峡工程
水沙调节
洛碛
王家滩
河床演变
数学模型
backwater area
Three Gorges Project
adjustment of water sediment condition
Luoqi
Wangjia- tan
river channel evolution
mathematical model
