Numerical Simulation Study On Dam-break Flow Of Da Nanchuan Reservoir

The safety of dam not only effect benefit of project but also relate to safety of people's life and property. The flood resulting of a dam breaking propagates quickly and often causes a calamity. During last century there were more than 200 failures of dams greater than 15m high. They have caused huge economic property and life loss. Many people suffered from the catastrophes of dam break.In this thesis, numerical simulation is a main way to try to study the waves where is from the breaking point to the zone of swash, with the help of experiments.At first,this article analysises the earth dam'failure forms and reasons. On this basis,instantaneous and gradual dam break are developed. Use of weir formula and water balance principle to establish instantaneous dam-break model. With the model to simulate the sudden and full or part destruction of a dam. According to the mechanism and process of piping dam-break,the gradual dam break about piping is developed. Orifice flow formula is adoped at orifice flow stage,weir formula is adoped at burst phase. Suppose the piping is rectangle,the breach is an echelon,growing wider with time. Combination of water conservation equation and sediment transport equation to establish gradually break model. used to simulate the the process of flow of breached dam failure caused by piping, the model calculat for the Teton Dam break, the results could better reflect the true situation.Secondly,boundary condition to breach flow discharge, a 2-D flood routing model based on MIKE21 is established. Rectangular mesh generation is adopted to calculation field. The validation of this method shows that it can deal with unsteady flows.Finally, the numerical models of dam-break and 2-D flood routing is calculated the breach flow and propagating routing of Da Nanchuan reservior. Take submerges the scope, the submergence water depth, the submergence lasted, the arrival time as the target, analyzes in the reservoir different situation the dam break flood magnitude size and excretes the current capacity flood most greatly in the downstream area of influence, establishes the Da Nanchuan reservoir flood risk chart. In particular, the program analyzes a different time of the flood on case1, and drew the flood inundation maps at different times, display of a flood of development; statistical calculation of the different options of inundated area, the affected population and economic losses, for the flood control work reference.