游荡性河道河势演变与稳定控制系统理论

With constraints of a wandering reach increase, evolution of river regime becomes more complex. Previous research efforts on evolution of river regime and river regulation for wandering reaches mostly stay at an empirical and experimental level, by which the aim of river regulation of the wandering reach in the Lower Yellow River—‘stabilize the main channel’ cannot be achieved without any new technological breakthroughs. Therefore, throughout theoretical analysis and modelling experiments, this project introducing the concept of ‘river system’, identifying the quantitative relation between constraint factors and regulating factors, revealed the evolving mechanisms of river regime influenced by finite controlling boundary conditions, gave a definition and threshold of the index for describing the stability of river regime of a wandering reach, explored ‘the harmony effect’ between unsteady water and sediment flow processes and finite controlling boundary conditions, which is measured by the expression of ‘the harmony index’. Based on above, the systematic method was applied to set up a generalized function, in which water and sediment flow processes and finite controlling boundary conditions are generalized independent variables and evolution of river regime is the dependent one. Taking this function as a core component, a systematic optimal model for stabilizing river regime was built. With operating the model in two directions (front and back), an optimal project for flow and river regulation was selected, which can not only satisfy the multi-constraints, but also stabilize the river regime. This research norm with dual cycle optimal processes filled the research gap of river regulation from practical, quantitative to theoretical, qualitative. And the optimal results would be an elementary achievement for river regulation to stabilizing river regime of a wandering river.

随着游荡性河道演变受到的约束越来越多，河势变化更加复杂。目前，游荡性河道演变与整治研究仍基本停留在经验加试验的层面，无法实现整治技术的突破，难以达到黄河下游游荡性河道“稳定主槽”整治的目标。因此，本项目突出河流系统概念，以厘清河势演变多维约束因子和调控因子及其定量关系为前提，融合理论研究、模型试验等手段，揭示有限控制边界（整治工程）作用下河势演变机理，提出游荡性河道河势稳定状态量化指标及相对稳定阈值，探讨整治工程与非恒定水沙过程和谐效应及不和谐度理论表达式；应用系统论方法构建以水沙过程和有限控制边界为广义自变量，以河势演变为广义函数的游荡性河道河势稳定控制系统模型；通过正反问题双向寻优求解，提出最大限度满足多维约束条件并实现河势稳定控制目标的水沙过程与工程布局优化组合方案。本项目将为河床演变与河道整治研究实现从经验到理论、定性到定量的跨越开创新思路，为实现由游荡到稳定的整治目标奠定基础。

通过资料分析、理论研究、模型试验等手段，本项目引入系统理论与方法，强化黄河下游河道治理的系统性和整体性，突出河道整治对整个游荡性河段河流系统本身行洪输沙功能提升和与社会经济、生态环境子系统服务功能的有机协同，厘清游荡性河道河势演变与稳定控制的约束因子、调控因子，以及彼此间的响应机制和下游关系，阐明水沙动力及有限控制边界对河势的控导作用，形成了一套相对完整的游荡性河道河势演变与稳定控制系统理论与技术体系。主要研究成果如下：.（1）构建了河势演变关键约束因子与调控因子的定量关系，提出了黄河下游游荡性河道河势相对稳定特征指标。（2）揭示了有限控制边界约束条件下游荡性河道河势调整机理，明晰了河势“上提下挫”与水沙动力变化的响应关系。（3）构建了基于河势稳定控制的水沙动力与河道边界不和谐度的理论表达式，提出了单个有限控制边界工程外形布置模式和工程群组布局准则。（4）提出了游荡性河道整治工程与和谐工程指标的不匹配度，建立了不同工程匹配度与和谐水沙动力阈值的定量关系，计算了不同河段的和谐水沙动力阈值；建立了不和谐度与河势相对稳定指标的定量关系，确定了实现黄河下游游荡性河道河势相对稳定控制的不和谐度阈值。（5）引入系统理论方法，构建了多维约束下的游荡性河道河势稳定控制系统模型，以河势稳定控制为目标，优化了小浪底下泄水沙过程和河道整治工程布局。开展了黄河下游游荡性河道河势稳定控制理论与技术的检验试验；并根据试验结果和原型工程实践，综合评价了改造后的工程布局与水沙过程的和谐度和河势稳定程度。.研究成果为游荡性河道整治提供了科学依据，实践结果表明游荡性河道河势逐步得到稳定。提出的稳定系统理论和工程布局可有力支撑国家战略要求实施的河道综合提升治理工程，河势稳定控制技术还可推广至世界其它江河的河道整治中。

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