柳河流域悬移质泥沙颗粒特征分析

为了探索流域悬移质泥沙变化特征及其与含沙量问的关系，选用柳河流域水文站泥沙观测数据进行分析。结果表明，由于沙源不同，非汛期悬移质泥沙粒径一般大于汛期，在流域上、下游d50随含沙量分别表现出增大和减小的趋势。在泥沙的分选沉降作用下悬移质泥沙粒径一般为上游大于下游。在上游，d50、大于0．05mm沙重百分数随含沙量的增大而减小，后又增大，小于0．01mm沙重百分数情形相反。在下游也可得出类似变化关系，但d50、大于0．05mm和小于0．01mm沙重百分数随含沙量变化的转折点不同。

Particle size characteristics of fluvial suspended sediment in Liu River basin, China

To explore the particle size characteristics of suspended sediment in the river, this paper has analyzed the suspended sediment data observed by Liuhe River hydrologic stations. During the low flow season, the clear base flow scours the bed, so the suspended sediment is relatively coarser than that in the flood season. In flood season most of suspended sediment comes from sheet erosion, which will primarily supply the fine sand. From upstream to downstream the particle size is fining for the reason of selective sedimentation. On the upstream, with an increased concentration the sediment size decreases when the concentration is <40kg/m3,and then increases when concentration>40kg/m3.There are similar relationships between suspended sediment concentration and sediment size on the downstream compared with the states on the upstream, but the turning point of sediment size with the increasing concentration is different.