黄河各冲积性河道输沙能力分析

Analysis on Sediment Transporting Capacity of Each Alluvial Channel of the Yellow River

利用实测资料,从泥沙组成、主槽流速、河道比降、断面形态等方面对宁蒙河道、小北干流河道、黄河下游河道、渭河下游河道的输沙能力进行了分析。结果表明:宁蒙河道比降最小、流速低、泥沙颗粒较粗、沉降速度大,是河道输沙能力小于其他冲积性河道的重要原因;北干流河段比降大、流速大但是泥沙颗粒较粗,特别是宽浅的断面形态直接影响着河道的输沙能力;下游河道尽管河道宽浅,但是泥沙颗粒较细,特别是大流量以及高流速决定了河道的输沙能力较大;渭河下游泥沙颗粒最细,沉降速度最小,窄深的断面形态决定了该河道具有极强的输沙能力。

The paper analyzes the sediment transporting capacity of Ning-Meng reach,Xiaobeiganliu channel,the lower Yellow River and the lower Weihe River from the aspects of sediment composition,velocity of main channel,channel gradient and section morphology by using the observed data.The outcomes show that a)the smallest gradient,low velocity,coarser particle of sediment and fast velocity of subsidence of Ning-Meng reach is the key reason causing the sediment transporting capacity smaller than that of other alluvial channels;b)the great gradient,fast velocity,coarser sediment especially the wide and shallow section morphology of Beiganliu reach directly affect the sediment transporting capacity of the channel and;d)the silt particles of lower Weihe River are the finest and velocity of subsidence the minimum.The narrow and deep section morphology has made the section having extremely strong capacity of sediment transport.