Theory And Technology Of Evironmental Risk Anlysis Based On The Dam-break Numerical Simulation In Haihe Basin

The most reservoirs in Haihe basin are of low standard, bad quality and serious condition. The people's life and property of downstream will be seriously damaged once accident takes place. Most of the studies were concentrated on one and two dimensional model in dam-break numerical simulation. Three-dimensional models from publication of literatures didn't consider the influence of the complex underlying surface in the downstream. The dam-break environment risk analysis was mainly concerning single influence factor, for example, life loss, economic loss, social and environmental influence. The research hotspot focused on the comprehensive risk analysis in recent years. Therefore environment risk anlysis of Haihe basin based on three-dimensional dam-break flood evolution numerical simulation is of important theoretical and realistic meaning, considering complex underlying surface.Based on studies at home and abroad, the three-dimension standard k ?εmodel of water-air two-phase flow coupled with Volume of Fluid (VOF) method was built. The strong-changing free surface of dam-break flood was simulated by VOF method and the influence of urban buildings of complex underlying surface on dam-break flood was considered in the condition of the boundary. Firstly, based on the flood information of dam-break numerical simulation, the attribute measure model of dam-break comprehensive evaluation was proposed, which contained influence factor, comment set, evaluation standard, factor weight, and attribute measure function. The attribute measure function was the most key part. The value of every influence factor was transformed to attribute measure and the comprehensive attribute measure was obtained by the sum of each attribute measure square combination, which was the combination of subjective weight and objective weight. According to the comprehensive attribute measure and the confidence criterion, the comprehensive risk degree could be identified. Secondly, the group-dam comprehensive risk sequence was gotten by the TOPSIS method. The group-dam risk was sequenced from the positive and negative ideal solutions.Combined with the dangerous reservoirs in the Haihe basin, dam-break flood evalution was simulated, the comprehensive evaluation of dam-break was obtained and the group-dam comprehensive risk was sorted by TOPSIS method. The typical dangerous reservoirs of type large II were chosen to illustrate the methods above, for example, Dongwushi reservoir, Lincheng reservoir, Youyi reservoir, Yunzhou reservoir and Miaogong reservoir. The results show as follows:(1) With the dam breach growing, time of flood submergence becomes shorter, depth and speed of water becomes larger and the dam-break severity increases in the five outburst forms of Dongwushi reservoir.(2) The comprehensive evaluation degrees for the five outburst forms of Dongwushi reservoir are extraordinarily serious.(3) According to the degree of harmfulness, the sequence of five typical dangerous reservoirs of type large II by the TOPSIS method in turn is the Dongwushi reservoir, Lincheng reservoir, Miaogong reservoir, Yunzhou reservoir, Youyi reservoir.