Risk Analysis Of Storm Surge Disaster And Study Of Emergency Evacuation In Costal Area

With biggest impact, highest frequency and largest loss, storm surge has become the greatest threatening marine disaster for China. Risk analysis and emergency evacuation research of storm surge disaster, as the important non-structural measures, have stand out. The occurrence of storm surge disaster is often accompanied with floodplain, overflow, dike breach and other complex phenomena, while the disaster scenarios would be difficult to predict for these related factors including natural environment, characteristics of storm surge, and mitigation measures etc. To this, most scholars ignored the prediction process and set a single scenario(flood plain or dike breach) to make analysis. For the risk analysis and emergency evacuation, hydraulic parameters were mostly extracted from empirical formula, lacking of numerical simulation, so that the results were unreliable. In terms of the comprehensive assessment on storm surge disaster, with numerous economic categories, large population mobility and complex social environment in coastal area, comprehensive evaluation is difficult to be performed, leading to the focus on economic loss, and the neglect of randomness for the indexes in comprehensive evaluation would make some deviations. In the research of emergency evacuation, the single evacuation way and static evacuation model couldn’t meet the various demands of dynamic evacuation network. Therefore, making 3D numerical simulation assisted by scenario analysis, along with risk analysis and emergency evacuation based on hydraulic parameters obtained from simulation is of great theoretical and practical significance for storm surge disaster.Aim at the above problems, a 3D mathematical model of numerical simulation for storm surge flood was established firstly; Secondly, considering the economic, life, social environmental factors and their randomness, the loss estimation and compressive evaluation of storm surge disasters were made by cloud model; Lastly, with the dynamic evacuation speed, a dynamic multi-objective model consisting of evacuees and vehicles was given for the evacuation system and individuals. Achievements are as follows:(1) Combining the core factors of storm surge disasters with scenario analysis technique, a complex scenario including floodplain, overflow, dike breach and other phenomena was built through logical deduction. Then, for the advantage in turbulence simulation, SST k-ω model coupled with VOF method was contributed to mathematical model of flood routing for storm surge, increasing the reliability of numerical simulation.(2)Firstly, according to the hydraulic parameters extracted from numerical simulation of storm surge, loss severities of economic, life, and social environment were determined by analyzing vulnerability of disaster bodies, which driving the formation of loss estimation model. Secondly, various aspects of disaster loss were prepared for index system and AHP coupled with PCA were used to calculate index weight. Cloud model was introduced for multi-attribute comprehensive evaluation to deal with randomness of these indexes, which made up for the lack of comprehensive evaluation.(3) Considering the speed variation and the different evacuation demands, a dynamic multi-objective evacuation model was established with the mixture of evacuees and vehicles. In the model, potential field method was used to improve ant colony algorithm for optimizing the path analyzing evacuation plan, which gives a great technical support for emergency evacuation.