水流条件诱导河湾形态变化试验研究

Experimental study on configuration variation of meandering channels caused by flow

蜿蜒型河道是冲积平原河流最常见的一种河型.在前人研究的基础上,从弯道的水流微观结构和输沙特征出发,利用弯道水槽试验,研究河湾的弯曲形态与来水条件及河床组成之间的关系,认识到来水条件是影响河湾形态的决定性因素,得到了河道曲率半径随流量增大而增大,即"大水造大弯,小水造小弯"的规律性认识,建立了弯曲半径与来水条件及河床组成之间的关系式,并利用丹江口水库运行后下游河湾特性变化进行验证,拟合结果与实测值基本相符.

Meandering channel is the most common channel form in alluvial rivers.Based on the research of predecessors and considering the microstructure of the flow as well as the characteristics of the sediment transport,by use of bend flume tests,this paper aims at finding the relationships between bend configuration and flow conditions and the constitution of river bed.Finally it comes to the conclusion that flow conditions are the key factor influencing the channel configuration and that the bend radius increases with the increase of discharge.Meanwhile,this paper puts forward a formula to calculate the curvature radius of channel whose reasonability is verified by the measured data of the downstream reach of Danjiangkou reservoir.This result can help to predict the development of bend configuration caused by flow variation,which is of great importance to both theory and practice.