河道采砂对湘江尾闾局部河段水流条件影响分析

Influence analysis of sand mining on flow condition of local channel in tail-streams of Xiangjiang River

为探讨采砂对河道水流条件的影响,基于水动力学方法,建立了采砂区二维水流数学模型,对湘江尾闾局部河段不同控采高程条件下采砂前后水流条件进行分析和预测。结果表明,在中低水条件下,河道采砂会使河段水面线略有降低,流速重新分布,分汊河段分流比发生变化;且随着采挖深度的降低,水位变化和流速变化逐渐减少。计算成果可为该河段的采砂可行性研究及采砂规模的控制提供科学依据。

The natural river channel is characterized as tortuous boundary, various terrain and complex flow. Based on the hy-drodynamic methods, the two-dimensional mathematical model of sand mining reach is established to analyze and forecast the flow condition of the tail-streams of Xiangjiang River at different mining controlling elevations before and after sand mining. The result shows that under middle and low water flow the sand mining will decrease the water surface profile slightly, redistribute the flow velocity and change the division ratio of the braided reach;and the changes of water level and flow gradually narrows with the reduction of the minning depth. The calculation results of this mathematical model can provide scientific basis for the feasibility study of sand mining in the reach and the scale control of the sand mining.