Location Optimization Of Evacuation Pick-up Points Based On Evacuation Needs And Convenience Of The Crowd

The rapid economic and social development,while promoting the growth of people’s living standards,has led to excessive regional population densities and increased urban vulnerability.When faced with large-scale emergencies,people are often at a loss and unable to cope with it,often resulting in great casualties and economic losses.In recent years,the international community has paid more and more attention to the study of emergency traffic evacuation plans in order to reduce casualties and property losses during emergencies.At present,it is obviously unrealistic to rely on private transportation only for emergency traffic evacuation according to China’s national conditions.Based on this,this paper selects the evacuation assembly site selection as the research object in the evacuation process based on public transportation.From the aspects of evacuation demand and convenience of the crowd,the optimization of the evacuation assembly site is considered.In order to reasonably select evacuation assembly points,firstly,this article systematically analyzes the key issues that should be paid attention to in the selection of evacuation assembly sites from the aspects of the characteristics of regional evacuation,the objectives and principles of evacuation assembly site selection.Second,provide basic information for the establishment of the site selection model by determining evacuation areas,dividing evacuation communities,and selecting alternative assembly points.Finally,the location optimization problem of evacuation junctions with evacuation needs and crowd convenience as the goals was proposed,and a dual-objective planning and location model was constructed.The site selection model assumes that the location and capacity of the candidate assembly points are known.The evacuation needs of evacuation cells can go to different evacuation nodes.At the same time,the coverage of different evacuation cells by the same evacuation node is different,and the coverage is expressed as a time-dependent piecewise function.Optimizing the total coverage of evacuation demand and minimizing the total walking time of evacuation demand as optimization goals,and taking the number of candidate assembly points,capacity limit,and maximum walking time limit as constraints.To achieve the optimal location of the evacuation assembly points,a generalized maximum coverage model and a P-median model are solved by comprehensively solving.In view of the complexity of the constructed dual-objective programming model,this paper selects the NSGA-II algorithm as the model’s solution algorithm,and uses C ++ programming to implement the model’s solution.Finally,in order to verify the applicability of the model in practical applications,this article takes the toxic gas leakage at the Lanzhou Petrochemical Refinery in Xigu District as an example,considers the characteristics of the toxic gas leakage process,delimits the evacuation area,selects the alternative assembly points,and substitutes the model to verify the solution.n the solution process,considering the impact of the evacuation requirements on the solution results,the evacuation requirements are set in different time periods(working days and non-working days),and compared and analyzed the results of the solutions.The results show that the model has certain applicability and reference value in practical applications.