黄河内蒙古段淤积泥沙洪水冲刷效应

为了探讨黄河内蒙古段淤积泥沙的洪水冲刷效应,于2012年对其三湖河口水文站河道监测断面汛期(7—10月)流量、悬移质泥沙含量以及洪水期间(2012年8月20日—2012年10月1日)悬移质泥沙含量、粒度百分含量的垂直变化特征与流量的关系进行了统计和分析。结果表明:(1)该次洪水具有峰高量大、洪峰过程在河段内持续时间长、洪水起涨和消退缓慢、峰形矮胖的特点;(2)洪水过程中,小于0.05mm的细颗粒泥沙在2 000m3·s-1左右的流量下就能输移通过,在2 000~2 400m3·s-1时输沙强度最大,对河道淤积泥沙可以达到输沙最优的效果;而粒径大于0.05mm的泥沙输移的效果不好。

Effect of Flood Scouring Channel Deposits in Inner Mongolia Reach of the Yellow River

Based on the hydrological data of water discharge, suspended sediment concentration and water level from Sanhuhekou hydrological station of the Inner Mongolia reach of the Yellow River from July to October, 2012, the scouring effect of flood on the channel deposits has been studied. And the relationship between water discharge and vertical variation characteristic of the suspended sediment concentration and grain-size from August to October, 2012, has been analyzed in detail. The results are as follows: High peak and large flood volume, sharp rising and declining, long flood process duration and the fat of peak shape are the characters of this flood. The vertical variation character of grain-size during flood process indicates that sediment particle size smaller than 0.05 mm can be transported under the flood water discharge below 2 000 m³·s^-1, and when the water discharge is at 2 000～2 400 m³·s^-1, the largest sediment transport can occur in the river channel. But the flood has poorly scouring effect on the coarse sediment (grain-size larger than 0.05 mm).