韭园沟与秃尾河流域淤地坝坝内泥沙粒径分析

Analysis of Sediment Grain Size of Warping Dams in Jiuyuangou and Tuwei River Watersheds

淤地坝是韭园沟与秃尾河流域重要的水土保持工程之一，淤地坝所处流域和工程结构的不同，淤积物的粒径大小存在差异。通过钻孔取样法采集了韭园沟流域21座淤地坝和秃尾河流域36座淤地坝淤积物样品623个，根据样品的颗分结果，分析得出韭园沟流域淤地坝坝内粗泥沙粒径主要为0．05 mm，秃尾河流域淤地坝坝内粗泥沙粒径主要分布于0．05～0．10 mm之间，说明淤地坝能有效拦截流域内的粗泥沙；两流域淤地坝均呈现库尾泥沙粒径总体大于坝前，库尾泥沙粒径的大小取决于入库泥沙粒径的大小，入库泥沙粒径越大，淤地坝对其分选效果越明显。

Warping dam is one of the important soil and water conservation projects in Jiuyuangou and Tuwei River watersheds. Because of the war-ping dam is different in watershed and engineering structure,the size of sediment in the dam is also different. Through drilling sampling method, it collected 623 samples in 21 warping dams in Jiuyuangou watershed and 36 warping dams in Tuwei River watershed. Analysis of sediment grain size distribution,the size of coarse sand in warping dams of Jiuyuangou watershed was 0. 05 mm,in warping dams of Tuwei River watershed was mainly 0. 05~0. 10 mm. The results show that the dam can effectively intercept the coarse sediment. The sand size of tail dam is larger than the front dam in the two watersheds. The sediment size of tail dam depends on the size of the sediment inflow the dam. The more coarse of the sedi-ments inflow the dam,the results of the separation effect are more obvious.