来沙条件对河床结构及推移质运动的影响过程

为了研究来沙条件对河床结构及推移质输沙率的影响过程,认识山区河流的推移质运动规律,选择在云南蒋家沟泥石流堆积体上进行野外试验。试验选择在非汛期进行,在试验河道采用人工加沙模拟上游来沙,对不同加沙率时的推移质输沙率及河床结构强度的变化过程进行连续监测。试验结果表明:上游来沙(或推移质运动)会使河床结构强度Sp降低,对河床结构造成危害,导致推移质输沙率的迅速增加;而推移质连续来沙必须先改变河道的河床结构强度才能增加推移质输沙率。在水流能量和河床结构强度相同的条件下,不同河流的推移质输沙运动相似。

Influence of supply sediment to streambed structures and bed load motion

Field experiments were conducted on debris flow deposits in the Jiangjia Ravine to study the effect of supply sediment on the riverbed structures and the rate of bed load transport to better understand the mechanisms of bed load motion in mountain rivers.The field experiments were conducted when there was no flooding.Sediment was fed into the experimental reach at different rates as the supply sediment while the bed load transport rate and the streambed structures were continuously monitoring.The results show that the supply sediment reduces the streambed structure intensity,Sp,which may destroy the streambed structure and sharply increase the bed load transport rate.Continuous bed load transport normally first alters the streambed structure and then increase the bed load transport rate.The bed load transport is similar in mountain rivers with similar stream powers and streambed structures.