摘要
三峡工程蓄水后“清水”下泄,坝下游河段将会长期处于严重不饱和状态,水流含沙量沿程恢复将会引起坝下游长距离冲刷,本文根据三峡工程蓄水前、后的实测资料分析了坝下游河道泥沙输移变化规律,探索不同粒径组沙量沿程恢复对河床冲刷的影响,得到以下结论:在蓄水初期d≤0.031 mm沙量恢复主要受河床补给与江湖入汇共同的影响,随着水库下泄该粒径组沙量递减,使得各站该粒径组年均输沙量均远小于蓄水前的水平,沙量恢复仍主要受河床补给与江湖入汇的影响,这是造成坝下游河道发生长距离冲刷的主要原因之一;在蓄水初期0.031 mm<d≤0.125 mm沙量恢复主要受河床补给的影响,但江湖入汇的影响较大,随着河床补给量逐渐减少,各站该粒径组年均输沙量均小于蓄水前的水平,沙量恢复仍主要受河床补给的影响,江湖入汇的影响逐渐减小,这也是坝下游河道发生长距离冲刷的主要原因之一;d>0.125 mm沙量恢复主要受河床补给的影响,蓄水初期该粒径组沙量在宜昌监利河段沿程恢复速率较快,且在监利站达到蓄水前的水平,随着时间推移,在宜昌监利河段沿程恢复且速率仍较快,在监利站达到最大值,其数值逐渐小于蓄水前的水平,这是造成坝下游河道冲刷重点集中在宜昌监利河段的主要原因.
Sediment concentrations in the downstream would be unsaturated in a serious long-term after the operation of the Three Gorges Project,since sediment concentration recovery causes long distance erosion in middle reach of the Yangtze River.Based on the field data collected after the operation of the Three Gorges Project,the sediment transport patterns in middle reach of the Yangtze River was analyzed,and the influence of sediment recovery along the river bed with different particle size groups on river bed erosion was explored.Result showed that:the recovery of sand content of d≤0.031 mm was mainly affected by the replenishment of riverbeds and the inflow of rivers and lakes in the early stage of water storage.With the decrease of the amount of sand with d≤0.031 mm,the average annual sediment transport amount of that group at each station was much smaller than that before the water storage.Recovery was still mainly affected by riverbed recharge and inflow of rivers and lakes,which was one of the main causes of long-distance erosion in the downstream channel of the dam.In the early stage of water storage,the recovery of sand volume of 0.031 mm<d≤0.125 mm was mainly affected by riverbed recharge,but the impact of rivers and lakes was significant.With the gradual reduction of riverbed recharge,the average annual sediment transport of the particle size 0.031 mm<d≤0.125 mm at each station was lower than that before the water storage,and the sand recovery was still mainly affected by riverbed recharge.The influence of inflow from rivers and lakes is gradually reduced,though this is still one of the main reasons for the long-distance erosion of the river downstream of the dam.d>0.125 mm sand recovery was mainly affected by riverbed recharge,in the initial stage of water storage,the sand content of this particle size group was faster in the Yichang-Jianli section,and it reached the level before the water storage in Jianli Station.In the Yichang-Jianli section,the rate was still relatively fast as time passes,peakin
作者
郭小虎
渠庚
刘亚
刘心愿
GUO Xiaohu;QU Geng;LIU Ya;LIU Xinyuan(Key Laboratory of River Regulation and Flood Control of MWR,Yangtze River Scientific Research Institute,Wuhan 430010,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2020年第2期564-572,共9页
Journal of Lake Sciences
基金
科技部重点研发专项(2016YFC0402303)
国家自然科学基金项目(51339001,51409017)
三峡水库科学调度关键技术第二阶段研究项目(SXSN14385)
财政部项目(12610100000018J129-5)联合资助
关键词
三峡工程
水库下游
不同粒径组
泥沙输移
Three Gorges Project
downstream of reservoir
different particle size group
sediment transport
