Research And Application Of Refinement Simulation Of Breakwater Floods And Flooding In Small Watershed Considering Infiltration

With the increase of extreme weather,strong rainfall over a short period of time increases gradually,which is a great test for the flood capacity of the ravine,and increasing the risk of dike embankments.In the flood control engineering measures,dikes play a key role.Once the outburst occurred,the breakwater caused by the flood of embankments is greatly destructive due to its large flow velocity and fast propagation speed,which will bring great impact on the lives and property safety of people on both sides of the Strait Threats.Based on the hydrodynamic model of small watershed and multidimensional coupled hydrodynamic model,and considering the influence of infiltration in the submerged area,this paper presented a detailed analysis on the flood and collapse of flood waters in small watershed.The main contents include:The paper studies the basic method of multi-dimensional coupling refinement of flood collapse.First,based on the principle of the continuity equations and equation of motion,the Abbott six-point implicit finite difference method was used to establish a one-dimensional hydrodynamic flood evolution model.At the same time,based on the two-dimensional Saint-Venant equations,a two-dimensional hydrodynamic model of inundated area is created.At the embankment breakout,the standard K-? two-pass principle of Saint-Venant equation and VOF method was used to establish a three-dimensional model of breach mouth fines according to PISO algorithm.The two-dimensional and three-dimensional transitional sections are used to couple the three-dimensional model of the breach with the two-dimensional hydrodynamic model in the submerged zone to simulate the diversion flood.And one and two-dimensional hydrodynamic coupling model was used to simulate the overflow of river.In order to fully reflect the terrain of the submerged area,the linear structure was precisely coupled with the boundary of the grid as the internal boundary condition.The saturation infiltration theory formula was used to study the influence of seepage in submerged area on the flood embankment process.Based on the principle of watershed distributed hydrological model,the distributed hydrological model simulation method was studied.According to remote sensing images,extracting DEM elevation data,and Arc GIS hydrological analysis module was used to divide the study watershed and extract attribute parameters of watershed.Then the sub-river basins and river sections were sorted,and a distributed hydrological model of Rujigou Basin was constructed to calculate the runoff and convergence process in the basin.Finally,based on the above research contents,a distributed hydrological model of Rujigou confluence area and a multidimensional coupling model of flood control of flood and collapse of flood defensive zone are established.The typical rainfall and flood data were selected to validate the model of river basin runoff and convergence.The typical example was used to verify the multi-dimensional flood fine coupling model of collapse flood.The flood inundation situation considering and not considering infiltration under two conditions was simulated,and the results of the calculation were compared and analyzed.The results show that infiltration has a great influence on the course of flooding and collapse of collapse flood.Therefore,the model proposed in this paper has good applicability in the calculation of flood risk of collapse flood in small watershed,and the calculation of this model is simple,the parameters of soil infiltration are easy to be determined,and the simulation accuracy is high.The model also provides an important reference and popularization and application value for flood forecasting and flood risk analysis of flood control in arid and semi-arid areas.