| The spur dikes of Maliangzi is a famous dangerous section on the Luanhe River.The place of spur dikes is close to the Maliangzi Village.Due to historical reasons,the spur dikes has not undergone a unified plan,forming a “dog-toothed” on the left bank of the river.The chaotic flow of the river is extremely easy to threaten the safety of the spur dikes,once the spur dikes lose its role,the water flow will directly brush the bank slope,which will cause great loss of people's property and safety.The improvement of the arrangement of the spur dikes has important significance in theoretical research and engineering application.Based on this,this paper uses the method of three-dimensional computational fluid dynamics(CFD)to summarize the factors affecting the water-sand movement of the single spur dike.Based on this,the state of water and sediment movement around the double dam and the multi dam on the natural channel is analyzed.The difference between the effects of single dikes and spur dikes on river remediation is proposed.The improved arrangement of spur dikes is proposed.The main contents of the thesis include the following four parts:The research on current spur dam flow characteristics and sediment movement is mainly based on physical tank model test or based on the study of water and sediment characteristics around single spur dike.Experts and scholars have already made more comprehensive research results in these areas,but lack of study on natural river channel and the water and sediment characteristics of spur dikes.Therefore,the RNG k-?turbulence model is used to simulate the water flow in the natural channel.The VOF model is used to treat the free water surface.The sediment model based on the Hillz number is used to simulate the riverbed sediment movement.In the process,a threedimensional numerical simulation method for simulating the movement of water and sand around the spur dikes on the natural river channel is proposed.According to the test data of the single sump tank made by experts and scholars in the past,the numerical simulation method used is verified,and the deviation of the calculation result is not large.The numerical simulation method can simulate the test data of the single sump sink well.And as a tool,firstly analyze the three-dimensional streamline of the water flow,explore the characteristics of the water flow around the single dam,and secondly add the different dam model of the structure,compare the two characteristics of the flow and sediment movement.Finally,a natural river model was established to explore the water and sand movement characteristics of non-submerged single dams in natural rivers,and to explore the effects of different lengths and different angles of pick on the movement characteristics of water and sand around the spur dike.Based on the study of the characteristics of water and sediment around the nonsubmerged single spur dike,the double dam model was set up on the left bank of the curved channel to explore the influence of different double dam layout on the water and sediment movement.There is a clear difference between the water and sediment movement around the spur dike and the single dam,and the combined effect of the double dam on the river regulation is summarized.According to the actual arrangement of the spur dikes in the Maliangzi section of the Luanhe River,and performing three-dimensional numerical simulation to compare the calculation results with the actual measured data.The calculated data can better simulate the measured data and compare the measured data.On the basis of the combined effect of remediation,adjust the length and the angle of the arrangement of the spur dikes in the Maliangzi section of the Luanhe River.The layout of the existing spur dikes and the layout of the modified spur dikes were compared to explore the characteristics of water and sediment movement around the spur dikes.The proposed layout scheme for the spur dikes system to further improve the actual project. |
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