不同峰型下河网泥沙控制的动力学模拟

Dynamic simulation of sediment control in a river network with different peak types

结合河网丰水期泥沙输移特点,建立了汇流模式下的河网泥沙排淤模型。模型重点体现支流不同河段上挟沙系数与冲淤量的反馈调节,突出了河网的自组织调节特性。利用模型计算了不同汇流情形下河段输沙效率。结果表明,河段输沙效率与汇流峰型相关,表现为无峰控制最优,其次为间歇控制、非线性控制和线性控制。对同一峰型,河段输沙效率与汇流流量涨落时步比及洪峰个数正相关。通过模型进一步模拟了不同峰型控制下河段冲淤量及挟沙系数的变化趋势,揭示了河网汇流排淤的动力学过程。

Based on the feedback mechanism or the self-regulation between sediment discharge capacity and river erosion-deposition state, a sediment transport dynamic model is proposed in this paper. The efficiency of sediment transport （EST） is studied by the model. The results verify the EST of river reach is related to differ- ent eonfluence peak type. The optimal controlling method is that of peak free. The EST with peak controlling flowering rate order in the sequence of descending is of interval control, non-linear one and linear one. The fluctuation ratio of flow and the number of flood peaks are positive correlated with the EST of river segment un- der same peak type. Furthermore, in order to reveal dynamic process, with different peak type, the changes of quantity of scouring or sediment deposition and sediment-carrying apability with time are discussed by model.