平原细沙河流动床泥沙模型试验的模型相似律及设计方法

Similarity criterions and design method of hydraulic models with a movable bed for plain rivers carrying fine sediment

在平原细沙河流的动床模型设计中 ,只考虑推移质运动的相似是不正确的 ,主要应考虑悬移质运动的相似 ,并且可以只考虑悬移质中床沙质运动的相似 .以相似函数形式表达的分段起动流速 (8)～ (11)式 ,可用以计算确定模型沙的粒径 ,使泥沙粒径的模拟符合相似理论的基本要求 ,从而提高其可靠性 .应用文中提出的模型相似律及模型设计要点 ,进行了长江八卦洲宝塔水道挖槽淤积动床模型的设计及试验 ,取得了地形冲淤验证试验的相似 。

It is incorrect that only the similarity of bed load is considered in the design of hydraulic river model with a movable bed. In fact, the similarity of suspended load is the main point to be considered, and it is only allowable considering the similarity of the part of bed material load within the suspended load. Initial velocity formulas (8)～(11) expressed in the form of similarity function type can be used to determine the diameter of the model sand, making the simulation of sand diameter meet demands of similarity theory. The reliability of the model is thus raised. By using the similarity criterions and design method, a movable bed hydraulic model for the channel siltation in Baota Waterway of Baguazhou Branch of the Yangtze River is carried out. Results of verification and forecast tests show that the bed configuration and sediment siltation in the model are in good agreement with those measured in the field measurements.