The Waterway Regulation Research Of Fluctuating Backwater Region Of Reservoir And Branching Reach With Bend

Bending braided river is one of the most popular type river in mountains of southwest china,such as Qingyanzi channel,Wangjiatan and Kowloon Beach in fluctuating backwater area of the Three Gorges.Navigation obstruction often appeared in this section due to changes in water and sediment conditions.Due to the complicated causes and mechanisms,the regulation of navigation obstruction is difficult.The characteristic of the rapid mainly manifested as curved,shallow,insurance,emergency.Owing to the limited research in fluctuating backwater area of bending braided river remediation and the urgent need to improve the channel level,it is necessary to make a deeper research on the causes of the obstruction and the regulation of the channel to solve the regulation principle,selection of regulation parameters,rational regulation arrangements of rapids and selection of the navigable channel.Based on the experiment on the physical model about waterway regulation of Bazinao beach group,this paper studied channel regulation problems of the reservoir in the fluctuating backwater area of bending braided river.This paper analyzed the river bed evolution laws,formation mechanisms of rapids,characteristics of navigation obstruction by the method of the combination of numerical simulation and physical model experiment,forecasted the trend of river bed evolution and proposed the regulation principles,selection of regulation parameters,rational regulation arrangements of rapids and selection of the navigable channel according to the movement characteristics of water and sediment.It provides scientific basis for the implementation of the waterway regulation project and the research results have reference value for channel regulation of similar river reach.Specific research contents include:1)Put forward the importance of this research topic through summarizing and presenting the home and foreigner's main contents and research status of reservoir fluctuating backwater area in bending braided river waterway regulation2)Based on the historical river terrain data,analysised the beach's recent and diachronic bed evolution rules.Besides,it studied the influence of hub dispatching on the regulation river betwean fengyi hub and mahui hub and analysised the causes and characteristics of navigation.On this basis,proposed regulation principles of “opening up a new channel,dredging the shallow area,returning water tank,improving the flow state”.3)The 2-d mathematical model of water flow is established and verified by the measured data.The mathematical model is established to study flow conditions and diversion ratio of the inlet.The final control scheme is proposed through numerical experiments and comparative study of different treatment schemes,which provides the basis for further research of the model test.4)Carried out fixed bed physical model experiment which checked by local moving bed experiment.On this basis,combined with the numerical model test results,made a deep study in respect of river ragulation,tested the stability of the trench and determined the appropriate regulation scheme.5)The technical summary of remediation measures,braided channel selections and maintenance of the navigation channel of the Bazinao beach group can provide valuable reference to the same type in the backwater area in bending braided waterway regulation.