Study On Site Selection And Layout Optimization Of Fixed Shelter Sites In Cities

After 40 years of reform and opening up,China's economy has developed rapidly,while the pace of urbanization has accelerated continuously.However,with the increase of urban population,the consequences of casualties and economic losses caused by various kinds of emergencies have been worse.Given this,compliant,legal and reasonable layout of fixed shelters in cities and towns can enable the affected people to be quickly evacuated after an emergency,minimizing the number of casualties and economic losses caused by unexpected events.In view of the current situation that the number of fixed shelters in most cities and towns of China is limited and the layout of the sites lacks scientific planning,this paper studies the site selection and layout optimization of urban fixed shelters.Firstly,through the theoretical research and practice of the evaluation system for selection of fixed evacuation sites,the fixed evacuation site inspection indicators are set according to the three criteria of site information,accessibility and supporting facilities of fixed evacuation sites.Then through those indicators,the effectiveness of fixed evacuation sites can be investigated and the basic data construction of alternative fixed evacuation sites and evacuation areas can be completed.Secondly,as the characteristic that different types of fixed evacuation sites have different evacuation distances,the multi-objective location model based on road attributes of fixed evacuation sites is constructed,which combined some advantages of P-center model on the basis of traditional P-median model.As advantages of the NSGA-II algorithm that lower complexity to compute,as well as quickly comparing the advantages and disadvantages of individuals among populations and retaining the optimal solution in the iteration process through the crowding distance,it is used to solve this multi-objective location model,in order to complete the primary selection of layout plans of urban fixed evacuation sites.Finally,through the analysis of food and beverage supplies as well as medical materials necessary for the affected people in the fixed evacuation site,the transportation cost model of the fixed evacuation sites is constructed considering the economy of the fixed evacuation sites.Through the calculation and comparison of the transportation cost of the rough selected plans,the optimal ones which give consideration to both accessibility and economy of fixed evacuation sites can be obtained.And ultimately,the optimal solution of the layout plan of the urban fixed evacuation sites is completed.