三门峡水库汛期排沙效果研究

三门峡水库汛期排沙是解决泥沙淤积问题、控制潼关高程的关键途径。"蓄清排浑"运用以来,非汛期蓄水期库区发生淤积、汛期降低水位运用排泄全年泥沙,基本保持了库区动态冲淤平衡。不同控制水位和入库流量过程存在不同的排沙效果,针对三门峡水库汛期排沙过程的差异,对"蓄清排浑"运用以来汛期排沙特征进行统计,分析了水库敞泄和不同控制水位运用对排沙效果的影响。结果表明,在汛期平水305 m、洪水敞泄的运用条件下,水库排沙具有多来多排的特点,汛期排沙总量与入库含沙量和水量密切相关;完全敞泄时库区冲刷取决于流量大小和敞泄时间,净排沙效率随着水量的增加和敞泄时间的延长而减小,冲刷效率降低;汛期控制运用期,当流量在1000 m~3/s以上时、水位在305～311 m也会产生一定的排沙,排沙效果取决于含沙水流在壅水段的滞留时间和出入库流量之比。研究成果可为三门峡水库运用方式的优化提供依据。

Research on the causes of sediment discharge of Sanmenxia Reservoir during flood season

The flushing operation of Sanmenxia Reservoir during the flood season is a key approach to handling the problem of sedimentation and restricting of Tongguan Elevation. Since the application of "Storing Clean Water and Discharging Muddy Flow"(SCWDMF), dynamic balance of scour and deposition in the reservoir has been generally maintained by lowering water level in flood season to flush the cumulative sedimentation during non-flood season. Different water levels operations and reservoir flow processes have different sediment flushing effects. In view of the differences in the sand discharge process of Sanmenxia Reservoir, statistical characteristics of sediment discharge in flood season since SCWDMF were adopted to analyze the influence of reservoir open discharge and water level operations on sediment discharge. The results show that under the operation of normal water lever of 305m and open discharging in flood period, sediment discharge has the characteristics of more coming and more discharging, and the total amount of sediment discharge in flood season is closely related to the incoming runoff and sediment concentration; When the reservoir is fully ungated discharging, reservoir scour depends on the flow rate and the open duration,with the net efficiency of sediment discharge decreasing with the flow increase and open duration extension; When the water level is controlled between 305-311m, sediment discharge occurred as the flow is above 1000m³/s with the efficiency depending on the retention time of the sediment-laden flow in the backwater section and the ratio of the inflow and outflow discharge. This research provides basis for the optimization of Sanmenxia Reservoir operation.