对长江芦家河浅滩段演变特性的新认识

根据实测资料,分析了长江芦家河浅滩段退水过程中沙泓冲刷流量(Q=10000～25000m3/s)的持续时间与当年航道发生青黄不接现象之间的联系.在此基础上,利用计算资料,分析了三峡建库以后来水来沙过程的改变对沙泓冲淤演变的影响趋势.

Analysis on Fluvial Processof Lujiahe Shallow Reach of the YangtzeRiver

The navigation channel of Lujiahe Shallow Reach of the Yangtze River is divided into two:sand channel and gravel channel by the channel bar named "qiba".The incoming condition of this reach including flow and sediment has a significant effect on thefluvial process of the navigation channel.Based on the field data and model experiments of moveable bed,the effect of process of the discharge on scouring of the sand channel after the flood peak has been analyzed.It has been found that the sediment deposited in thesand channel during the flood season will be scoured when the flow discharge keeps in the range of 10000～25 000 m³/s.After the construction of the Three Gorges Project,the incoming condition of flow and sediment in this reach will change greatly,in which the duration of the flow discharge keeping in the range of 10 000～25 000 m³/s will increased to some extent,therefore the phenomenon of temporary cutt-off of the navigation channel will be improved.