| Landslide damming river is very common in the world, and the stability of the landslide dam is rather low. The landslide dam may break under the effect of the earthquake or storm, and the momentary huge flood leads to a catastrophic damage in downstream watercourse and banks. So it is of great significance to carry out outburst flood computation, and the peak discharge directly determines the degree of the dam break flood disaster. Reasonable peak discharge calculation is of great significance to the risk assessment of landslide dam, the landslide dam management and the disaster prevention and reduction of the downstream. But the ancient landslide dam breaking has less research results. The research of Xuelongnang paleolandslide-dam breaking is the first information of this landslide dam. It has an important significance for the next study and enrich the information of paleolandslide-dam.Now there are many methods to calculate the peak discharge in the world, and they are calculated based on different principle. In this paper, several methods are used to make an inversion calculation of the peak discharge of the Xuelongnang paleolandslide-damon the Jinsha River, and make a comparison and analysis. By the inversion calculation, the outburst peak discharge of Xuelongnang paleolandslide-dam is between 10168 ? ~16091 ?.This paper introduces Fluent software to do the numerical simulation of dam break flood, based on the finite volume method and VOF(Volume of fluid) method, dam break model established by Gambit. Two dimensional simulation and three dimensional simulation of dam break flood are carried out in this paper. Two-dimensional simulation using two kinds of methods, the trapezoidal breach with a slope at the bottom and trapezoidal breach without a slope, were compared and analyzed. The results show that the bottom with slop accelerate the dam break flood routing, prove that the erosion to the bottom ofbreach by flood will accelerate the dam breaking and expedite the outburst flood in the process of landslide dam breaking.The three dimensional model use the trapezoidal breach, without slope on the bottom. Three dimensional numerical simulation result show that the turbulence at the edge of the outburst flood is the main reason of the formation of mix deposit downstream of the landslide dam. Thedam break flood discharge obtained from three dimensional numerical simulationis 9087 ? at 300 mdownstream of dam,13205 ? at 200 mdownstream of dam, 13205 ? at 100 mdownstream of dam and 23419 ? at the bottom of dam. Regression equation method and the method of using the sediment particle size inversion break dam flood peak are similar to the results, both and mutual verification. |
