水库支流异重流入汇干流动力过程试验研究

Entering reservoir of tributary hyper-concentration density current could in a short time leads to a substantial adjustment at local topography; for example, entering Liujiaxia Reservoir of tributary Tao River, even may form the second reservoir, and thereby constrains reservoir comprehensive benefits. Up to now, researches concerning density current and its backward flow are confined to mainstream density current, and there is little research on tributary density current. The project will combine basic test with theoretical analysis of sediment dynamics. At the basic level, it will study movement and diffusion processes of density current at intersection zone, water and sediment transport, deposition morphology and so on，and clear the response relationship of deposition morphology and influence factors. At the application level, under the condition of different water level, it will study density current transport and sedimentation law, put forward response mechanism of reservoir operation on sedimentation and backward flow of tributary of, and lay the foundation for the practical application. Researches of the project are of important theoretical and practical significance on fully mastering water and sediment transport and sedimentation at intersection zone, improving theory level of predicting reservoir density current sediment ejection and reservoir comprehensive benefits, richening river sediment dynamics, river simulation technology and so on.

多沙河流水库支流高含沙异重流入汇，例如，刘家峡水库支流洮河入汇黄河，在短时间内可引起局部地形大幅度调整，甚至有产生二级水库的可能，从而在一定程度上制约了水库综合效益的发挥。目前，关于水库异重流入汇及倒灌的研究成果大多限于干流异重流入汇及倒灌支流，而关于支流异重流入汇研究较少。本项目在基础层面，拟基于水沙动力学的基本理论与基础试验，研究支流异重流入汇水流流态，交汇区异重流运动及扩散过程，浑液面变化规律，水沙输移规律及交汇区淤积形态等，明晰交汇区局部淤积形态及影响范围与影响因素的响应关系；在应用层面，分析不同水库调度下支流异重流运行及泥沙淤积规律，提出支流异重流淤积倒灌对水库调度的响应机制，为实际应用奠定基础。项目研究成果对于充分掌握干支流交汇区水沙输移规律及泥沙淤积部位，提高水库异重流排沙预测理论水平及水库综合效益，丰富河流泥沙动力学、河流模拟技术等学科内容均具有重要的理论和实际意义。

项目以支流异重流为研究对象，基于水沙动力学的基本理论,通过实测资料分析了多沙河流支流异重流入汇区沙坎演化过程及成因，研究了拦门沙坎对入库水沙、水库调度及淤积形态的相应关系；结合河流动力学、异重流等科学理论的分析方法，研究了异重流入汇区水沙演化及淤积约束机制；借助水槽试验，分析了研究支流异重流入汇区水沙演化规律，提出交汇区异重流浑液面变化规律及异重流头部运行规律，获得支流异重流淤积倒灌长度及其对影响因素的响应。项目研究成果对于充分掌握干支流交汇区水沙输移规律及泥沙淤积部位，提高水库异重流排沙预测理论水平及水库综合效益，丰富河流泥沙动力学、河流模拟技术等学科内容均具有重要的理论和实际意义。