Three-dimensional Numerical Simulation Of Hydraulic Characteristics Of Dike Breach Based On FLOW-3D

Embankment is the main building used by human beings to resist floods.Once the embankment breaks,it will cause incalculable property losses,and even threaten people ’s lives.If we can grasp the law of dike breach development and the hydraulic characteristics of breach flow,it will be of great significance to study the mechanism of dike gradual breach and guide the closure of breach.Taking an actual embankment as an example,this paper studies the hydraulic characteristics of the embankment breach based on numerical simulation,and studies the hydraulic characteristics of the embankment breach and the gradual breach process of the embankment breach.Mainly carried out the following aspects of research :(1)In order to verify the accuracy of the selected model,FLOW-3D is used to simulate two widely used classical examples of one-dimensional burst flow and twodimensional asymmetric dam break.The numerical simulation results are compared with the water surface line and velocity field of numerical simulation in the literature of C.Biscarini and A.De Maio,which proves the feasibility of FLOW-3D simulation of local instantaneous flow.(2)The local instantaneous breaches with different breach shapes and different breach widths are set up in the embankment bend section,and the numerical simulation is carried out by FLOW-3D.The water surface profile,flow field distribution,flow velocity and water depth near the breach are analyzed,and the variation of hydraulic characteristics near the breach under different breach shapes and different breach widths is studied.The numerical simulation results of different breach shapes in the bend section of the embankment show that the maximum flow velocity of different breach shapes is V-shaped,U-shaped,T1-shaped,T2-shaped and rectangular,and the average water depth is V-shaped,T1-shaped,U-shaped,T2-shaped and rectangular.The numerical simulation results of the breaches with different widths in the bend section of the embankment show that the average water depth and flow velocity gradually decrease with the increase of the breach width.(3)The numerical simulation analysis of the gradual breach process of the embankment is carried out by using the sediment model.By comparing the physical breach experiments in the literature,the morphological changes of the breach in the numerical calculation are basically consistent with the experimental results,and the widening process of the breach gate is the same.The feasibility of FLOW-3D simulation of gradual breach is verified,and the development law of the breach in the bend section of the embankment and the flow change characteristics of the gradual breach of the embankment breach are studied.The calculation results show that the breach is V-shaped downward erosion.When the breach develops downward to the foundation,the breach will widen to both sides in an inverted trapezoidal shape.In the direction of parallel burst flow,the breach starts from the outlet of the initial breach of the embankment and develops to the foot of the embankment on the side of the water slope.The flow velocity of the outburst flow increases first and then decreases with time,and the position of the maximum flow velocity will move towards the flow direction with the outburst time.