| Poyang Lake is situated at the northern part of Jiangxi Province, south of the Yangtze River is the largest freshwater lake in china. Consist of five rivers (in concluding Gang Jiang River, Fu he River Xinjiang River, Yao He River and Xiuhe River) and other catchments around the lake. but with the modernization and industrialization rapid adware, Poyang Lake water ecology,water environmental problems are becoming increasingly serious. the original ecological rivers no longer excites and has seriously affected the economic and social sustainable development in Jiangxi.To a summary for the research situation of model sand in this paper. By analyzing actual historical material of the Poyang lake sediment, preliminary determine the lake sediment characteristics and the prototype graded curve of Poyang Lake.The choose the type of sand for substantiality model is a key technology, it directly influences the reliability of the result of experiment and similarity of the sand motion and riverbed distortion. It is incorrect that only the similarity of the 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.In the middle ground and fine sand river bed model sand, the basic similar dynamic conditions are similarity of flow movement and similarity of sediment movement. The velocity of flow scale of Froude number similar and resistance similarity is not consistent, and water resistance is bed sand particle size and water of the strength of the functions. The relevant materials diameters scale form is also inconsistent in the sediment movement in similar, and it is relevant with water movement, making the sediment particle size is very difficult to demines, so have to according the nature of the problem to choice, select the main as design basis,the minor is allowed to have certain deviations.According to the needs of the research problem, this paper puts forward the design method of materials diameters scale, according to these methods can be basically in line with similar requirements of sediment diameters scale. In this paper, through the running proposed materials diameters scale of design method of Poyang Lake, initial determine the sediment materials diameters scale, the last starting incipient velocity test of model sand in the flume of glass, with nominal diameter were 0.063mm,0.12mm,0.21mm,0.28mm and0.43mm 5 groups of sediment as an example, deduce incipient velocity of plastic material sand in different conditions of individual actions,small actions,a large of number of actions, and provide the technical guarantee for model choose sand. |
