2017年第1号洪水期间小浪底水库异重流分析

Analysis of Density Current in Xiaolangdi Reservoir During the No.1 Flood in 2017

2017年黄河第1号洪水期间,在小浪底水库高水位运用的情况下,通过科学调度,成功地塑造异重流并排沙出库。根据实测资料对小浪底水库进出库水沙条件、水库运用情况、水库异重流演进及运动特点、异重流排沙情况等进行了分析总结。结果表明:此次异重流潜入点在距坝46.2 km的HH28断面,测点最大流速为0.49 m/s,最大含沙量为55.1kg/m^3,异重流厚度为0.77 m;从异重流潜入到排沙出库共计历时约为68 h,异重流运行速度约0.19 m/s;随着第1号洪水的演进,HH09、HH04、HH01断面的异重流流速、厚度整体上呈现先增大后减小的趋势;异重流塑造期入库总沙量为5 020万t,最大入库含沙量为477 kg/m^3,出库总沙量为21.65万t,最大出库含沙量为2.70 kg/m^3,水库排沙比为0.43%;此次异重流塑造过程为后期水库溯源冲刷排沙创造了有利条件。

During No.1 flood in 2017,under the condition of high operation water level,by scientific control,density current successfully shaped inXiaolangdi Reseroir and discharged. According to the measured data,the paper analyzed inflow and outflowsediment conditions, reservoir operation,the evolution of density flow and sediment desiliting. The results show that plunging point is in the cross section HH28 which is 46.2 km to the dam,the maximum velocity is 0.49 m/s,the maximum sediment concentration is 55.1 kg/m3 and the thickness of density current is 0.77 m. The move duration from plunging point to the dam is about 6 8 h and the average velocity of density current is about 0.19 m/s. With the evolution of No.1 flood, the velocity and thickness of density current in cross sections HHO9,HHO4 and HH01 decreased at first and then increased. The total amount of input and output sediment are 50.2 and 0.22 million tons respectively,the maximum of input and output sediment concentration are 477 and 2.7 kg/m3 respectively and the sediment deliver ratio is 0.43%. The shaping of density cur-rent provides favorable conditions for the later stage headward erosion.