水库异重流淤积成因分析及前锋运动规律

汛期暴雨冲刷河道两岸形成浑水入库,在一定条件下会潜入水库底部形成异重流。若上游降雨历时较短,形成的异重流因失去后续浑水补给而停止运动进而造成水库淤积。针对这一问题,基于水库异重流挟沙能力的计算公式,分析异重流造成水库淤积的原因,即异重流的超饱和输沙和沿程流量损失。针对异重流因沿程流量损失而发生的水库淤积,对失去后续浑水补给的异重流进行水槽试验,分析坡度和浑水入流流速对异重流前锋厚度及运动速度的影响。试验结果表明:坡度或浑水入流流速越小,失去浑水补给的异重流前锋运动速度越慢,前锋厚度减小越快。

Study on reservoir sedimentation caused by turbidity currents and experimental study on front movement

Turbidity currents are formed in certain conditions when the rainstorm scours riverway with lots of sediments,plunging into the bottom of the reservoir.If the rainfall duration is short and the runoff quickly reduces,turbidity currents will lose the follow-up muddy water supplies,stop and cause reservoir sedimentation.Factors of reservoir sedimentation caused by turbidity currents are analyzed via formulas of sediment transport.Front thickness and motional time of turbidity currents without supplement are studied via experiments in different conditions.Meanwhile,influences on front of turbidity currents by slope and muddy water inflow are analyzed.The results show that in the condition of the experiment,the smaller the slope or the muddy water inflow velocity is,the faster front thickness decreases and the slower the movement forward of the turbidity currents without follow-up supplement is.