冲积河流滩槽水沙配置机理研究

Main research contents：A compound channel with the main channel and floodplains is a common phenomenon in fluvial rivers．When the discharge is smaller, flow runs in the main channel. Otherwise, flow would enter floodplains. Some effects of overbank flow must be onsidered in flood control, channel training and floodplain exploitation etc. In this research. On the basis of the generalized flume in compound channels that can reflect the basic characteristics of typical alluvial rivers, combined with some methods of field investigation, data analysis and theoretical study. These distribution characteristics and the exchange mechanism of flow and sediment and the dynamic response process of the bed surface in main channel and flood plain in alluvial river are analyzed by the numbers. The main research contents include: (1) To research of some distribution characteristics of water flow, sediment concentration, sediment grading and erosion and deposition of river bed in compound channel. (2) To explore the response mechanism between some factors of flow and sediment and the distributions of the suspended sediment, the bed material and the erosion and deposition of river bed in compound channel. (3) To establish the coupling relationship and balance threshold between the dynamic factors of flow and sediment and the sediment allocation in main channel and flood plain. (4) Put forward to the basic modes of allocation optimization of flow and sediment in compound channel..Innovation point: By comparing the experimental data of the fixed bed and the movable bed rivers, quantitative grasp these relations between the erosion and deposition in river bed and the distributions of flow and sediment in compound channel. Some balance thresholds and basic mode are established by these response relationships between the variation of flow and sediment and sediment configuration in compound channel..Expected results: Some response relationships in the different factors of flow and sediment and the morphological parameters of channel and plain will be established in alluvial river. The reasonable allocation mechanism of typical flow and sediment will be put forward in compound channels.

主要研究内容：通过建立能够反映典型冲积性河流基本特征的概化复式河道，结合现场调研、资料分析和理论探讨等基本手段，深入分析冲积性河流滩槽水沙的分布特性、水沙交换机理和床面动态响应过程，主要研究内容包括：①研究不同水沙组合和床面组成下复式河道的滩槽水流、含沙量、泥沙级配及床面冲淤的分布特征，②探讨水沙因子与滩槽悬沙、滩槽床沙及滩槽冲淤分布之间的响应机理，③建立水沙动力因子与滩槽泥沙配置之间的耦合关系和平衡阈值，④提出滩槽复式河道泥沙优化配置的基本模式。.创新点：通过滩槽定床和全动床加沙的结果比较，定量把握床面冲淤变化对滩槽水沙分布的影响；通过分析水沙变化与滩槽泥沙配置之间的响应关系，建立复式河道滩槽泥沙配置的平衡阈值与基本模式。.预期成果：建立冲积河流滩槽复式河道不同水沙因子与滩槽形态参数之间的响应关系，提出典型复式河道的滩槽水沙合理配置模式。

滩槽复式河道是冲积河流中最为常见的平面形态，其所在区域往往也是人口密集和经济比较发达的地区。项目主要研究内容是通过建立能够反映典型冲积性河流基本特征的概化复式河道，结合现场调研、资料分析和理论探讨等研究手段，深入分析冲积性河流滩槽水沙的分布特性、水沙交换机理和床面动态响应过程，提出以滩槽平衡阈值为基础的泥沙配置模式和调控方式。. 本项目通过对松花江及黄河下游的现场调研和分析，采用遥感影像解译等技术手段，首次明确了松花江不同河段的滩区分布和面积大小，分析了松花江干流的河势变化和滩槽分布特征，得到了干流河势基本稳定、河道和滩地宽度上大下小、主槽宽度和滩槽水深沿程变化较小等基本结论。通过现场调研和数据分析，结合滩槽宽深比和水沙比等关键参数，明确了滩槽实体模型的概化原则和设计方法，建立了以松花江典型河段为特征的概化实体模型；基于Windows系统和无线WIFI技术，开发了全因子实体模型自动测控系统，实现了模型进口清水自动控制子系统、浑水自动控制子系统和尾门控制子系统的集成控制和模块化，具有很强的通用性，具备了基于互联网技术进行实体模型试验的全过程控制；开展了不同水沙组合的方案试验，对比分析了不同水沙条件下滩槽水沙及床面冲淤的分布特征，揭示了滩槽水沙动力因子与滩槽形态之间的相互作用机理和滩槽水沙分布的区域性特征，提出了不同分区界线的计算方法和滩区利用的临界阈值。. 项目研究首次揭示了松花江干流主槽宽度和滩地水深的稳定阈值，建立了滩槽宽度比与主槽宽度、滩槽水深比与滩地水深之间的相互关系，提出了冲积河流宽滩区治理的基本原则、治理方法和调控技术。项目在实体模型测控技术、宽滩区水沙分布的区域性特征、宽滩区稳定临界阈值和治理与调控技术上取得了创新性研究成果，丰富和完善了河流动力学和河床演变学的学科内容，为黄河、长江、嫩江及松花江等冲积性河流的防洪整治和生态发展的协同高质量发展提供技术支持。