Research On Flow Condition For Navigation In The Entrance Area And The Transitional Reach Of The Navigation Structures

Based on the collection of domestic and foreign technical literature, learning about the panorama of the research background, summarizing the problem in the use of the limiting value of flow condition for navigation at present. Selecting different rank of the channel classes and the different region project, and through the physical model, the ship model and the scene flow test, the research studied the navigation condition of ships (team) in different navigation channels classes with different layout of the entrance area of the approach channels and different linkage section of the navigation structures, and proposed the limiting values of the flow condition are proposed. The main research results are as following:(1) The ship model can pass across influentially the entrance area, when the longitudinal current velocity and the transverse current velocity are all in criterion permission scope in the entrance area of the approach channel. But the ships' navigation condition in the entrance area has close relation with the layout of the linkage section. Regarding with the same shore connection linkage section, there is little influence about the navigation in the entrance area; But for the different shore connection linkage section,there is compared bigger influence about the navigation in the entrance area.(2) Looking from the navigation condition of different layout of the linkage section, the same shore connection is better than the different shore connection; For the different shore connection, the angle between connection section and the main stream flow is smaller, the navigation condition is superior.(3) Based on the characteristics of the entrance area of the approach channel and the linkage section arrangement in the different layout of canalization key works, which haveing built, building and unbuilt, such as the Jialing River, the You River, the Xiang River, the Songhua River, the Yangtze River, the Yuan River, the Red River and the Lancang River and so on. Then propose the arrangement principle of the entrance area and the linkage section of the navigation structures.(4) Synthesis the results of the field observation of the navigation hydro junction, the flume test, the hydraulic model test and the mathematical model calculation, the target limiting value of flow condition for navigation which satisfies the ships safe under the different channel classes and layouts of the linkage section was proposed.(5)The practical project and the model test was analysed, for guaranting of the safety of the boat safety with pass in and out. It is appropriate that the flow condition in the entrance area is adequate, according to《the instructions of the Navigation standard of inland waterway》. If the flow directions (the longitudinal current velocity, the transverse current velocity and the return current) in the entrance area of the approach channel exceed the allowance of the Navigation standard of inland waterway, the flow overrun range shoud be reduced and the length shoud be shorter than the 2/3 ship length.(6) If the flow conditions in the entrance area of the approach channel and the linkage section cannot meet the requests, may take some suitable engineering measures to improve the flow condition for navigation, according to practical status, including: alter the fluctuation length of the dividing dike , open the hole on the entity dividing dike head, adopt of thoroughly the spatial guide wall, constructing the spur dike, the training dike, the diversion pier or the partial excavate the channel width, excavate the mountain for continuous flow. The adoptive engineering measures must be examined through the hydraulic over-all model test and the ship model test.