黄河下游滩区水沙演进与洪水风险评估综合模型研究

The floodplain domain is a base of survival and development of local inhabitants in the LYR, and it is also an important site for flood routing, sediment retention, and sediment silting. Therefore, Flood risk is still a main factor of restricting the socio-economic development on the floodplain domain. It is necessary to conduct the research into modelling of flow and sediment routing during overbank floods and assessment of flood risk to people and property. In this study, the Lower Yellow River is taken as an object of study. Various methods are adopted to investigate the process of flood routing and the safety of flooded subjects, including field data analysis, mechanics-based theoretical analysis, numerical simulation and laboratory experiments. Firstly, formulae are presented to calculate the two-dimensional movable bed resistance in the main channel and vegetation roughness on the floodplain area, which accounts for the characteristics of the Lower Yellow River; mechanics-based formulae are proposed to estimate the safety degrees of people and property in floodwaters; and the influence of sediment concentration and rate of bed evolution on the process of flood routing is investigated. The two-dimensional morphodynamical model is refined, which is based on the finite volume method with unstructured triangular mesh, and the refined model is then integrated with the module of flood risk assessment of people and property, which comprises an integrated numerical model for flood risk assessment over floodplain areas. Finally, the proposed model is used to predict the potential loss of flood disaster over a typical floodplain area under different scenarios, which would provide the related reference to floodplain flood risk management and various regulation modes.

黄河下游滩区既是当地群众赖以生存的场所，同时也承担蓄洪、滞洪及沉沙的功能，故洪水风险仍是滩区社会经济发展的主要制约因素。因此开展滩区水沙演进模拟及洪水中群众生命财产安全评估的研究，是当前迫切需要解决的科学问题。本研究将以黄河下游为研究对象，采用实测资料分析与力学理论分析相结合，模型试验与数值模拟相结合的方法研究下游水沙演进机理及滩区洪水风险评估方法。首先建立适用于黄河下游特点的二维动床阻力及滩区植被阻力的计算公式，提出基于力学机理的洪水中人体与财产安全程度的计算方法，揭示含沙量大小与床面冲淤速率对洪水演进的影响机理；然后完善已有基于无结构三角网格及有限体积法求解的二维水沙动力学模型，并结合人体与财产安全程度计算模块，建立滩区洪水中群众生命财产安全评估的二维综合模型；将该模型应用于黄河下游的典型滩区，预测滩区各种工况下可能的洪水风险，为滩区洪水管理及不同治理模式研究提供技术参考。

黄河下游滩区既是当地群众赖以生存的场所，同时也承担蓄洪、滞洪及沉沙的功能，故洪水风险仍是滩区社会经济发展的主要制约因素。因此开展滩区水沙演进模拟及洪水中群众生命财产安全评估的研究，是当前迫切需要解决的科学问题。本研究以黄河下游为研究对象，采用实测资料分析与力学理论分析相结合，模型试验与数值模拟相结合的方法,开展了近期黄河下游河床演变过程与特点、下游水沙演进机理及滩区洪水风险评估方法的研究。首先利用实测资料，结合基于河段尺度的计算方法，分析了黄河下游河道水沙变化及冲淤过程、断面与平面形态调整及河段平滩流量变化，揭示了近期黄河下游的河床演变特征和规律；同时还建立了适用于黄河下游特点的主槽动床阻力及滩区植被阻力的计算公式，提出了基于力学机理的洪水中人体与财产安全程度的计算方法，揭示了含沙量大小与床面冲淤速率对洪水演进的影响机理。然后完善了已有基于无结构三角网格及有限体积法求解的二维水沙动力学模型，并结合人体与财产安全程度计算模块，建立了滩区洪水中群众生命财产安全评估的二维综合模型。将该模型应用于黄河下游的典型滩区，预测了滩区各种工况下可能的洪水风险，为滩区洪水管理及不同治理模式研究提供了技术参考。项目研究期间，负责人获聘教育部“长江学者”特聘教授，以及国家杰出青年科学基金资助，此外还获省部级一、二等奖励3项及英国皇家工程院国际合作奖1项。共培养水力学及河流动力学方向的研究生7名，其中博士研究生4名，硕士研究生3名；拟出版专著2部；取得软件著作权7项；申报国家发明专利3项；发表（包括已接受）相关论文44篇，其中SCI收录13篇，EI收录9篇。本项研究成果不仅丰富了河床演变学与水沙过程模拟的基础理论，而且还为下游滩区不同治理模式研究及洪水风险管理提供了技术参考。