Study On Reconstruction Process Of Curved Bifurcation Channel Under Unsaturated Sediment Flow

After the operation of the Three Gorges Reservoir,the water and sediment conditions of the downstream river channel changed.When the total amount of incoming water was basically unchanged,the amount of sediment discharged was greatly reduced,and the sediment was coarsened to form a typical unsaturated sediment transport.Under this circumstance,the downstream of the reservoir will be rebuilt,which will have an impact on flood control,shipping and shoreline utilization.Therefore,the research on the reconstruction process of the curved bifurcation channel under the condition of unsaturated sediment transport has important theoretical and practical significance.On the basis of summarizing the existing research results at home and abroad,this paper combines the methods of prototype observation data analysis and generalized model test to comprehensively study the reconstruction process of the curved bifurcation river in the case of unsaturated sediment transport,and its The difference and common point of the bed making process under saturated sand transport.(1)Through the generalized model bed test,the study reveals the changes of hydraulic factors such as water surface ratio,cross section velocity distribution,bed shear stress and split ratio in the diversion channel,the ramp section and the confluence zone of the curved bifurcation channel under different water flow conditions.law.It also illustrates the sudden changes of these hydraulic factors in different regions of the curved branching channel under the flat beach flow.(2)Through the analysis of prototype observation data and the generalized model test,the analysis reveals the general rule of erosion and sedimentation of the curved and bifurcated channel under the condition of saturated sediment transport and unsaturated sediment transport,and the evolution law of the diversion zone,the ramp section and the confluence zone,and the vertical section of the water surface.The change in the ratio.(3)Through the analysis of prototype observation data and the generalized model test,the analysis reveals the same points and differences in the process of riverbed reconstruction under the condition of saturated sediment transport and unsaturated sediment transport,and analyzes the curved watershed channel under two kinds of water and sand conditions.The link in the process of riverbed reconstruction.