Study On The Seismic Damage Of Regional Buildings And Dynamic Evacuation Simulation Based On Shortest Path

China is one of the countries that suffered the most losses from earthquake disasters in the world.In recent years,with the continuous progress of urbanization,the population and wealth are increasingly concentrated in cities.Therefore,the population and total economic in cities are increasing day by day.Once a devastating earthquake occurs near the city,it will cause huge casualties and economic losses,so the construction of urban disaster prevention planning system becomes more and more important.Although the uncertainty of earthquake still exist,the damage state of buildings,casualties and evacuation can be effectively evaluated when earthquakes of different intensities occur.Researching on building damage,casualties evacuation from the regional perspective can provide important reference for the construction of urban disaster prevention planning system and enhance the comprehensive capacity of urban earthquake disaster prevention.Since the whole process needs to achieve the evaluation objectives of fast evaluation speed,simple parameter acquisition and accurate evaluation results,this paper uses the simplified model method and the response spectrum method based on capability requirement to evaluate the damage state of buildings.In addition,It also simulates the evacuation of people under earthquake,and gives the improvement scheme.The main research contents are as follows:(1)A multi-degree-of-freedom shear model and a multi-degree-of-freedom flexural-shear model are used for the simplification of refined finite element models.The modeling process is given by combining with the domestic and foreign research.Through comparing the results of earthquake response with refined finite element models,the feasibility of the method is proved.A method based on response spectrum is proposed to evaluate the damage state of the structure,which greatly reduces the computation.Based on the results of the earthquake damage discrimination of the fine finite element model,the accuracy of the earthquake damage discrimination method by the simplified model and the response spectrum method is evaluated.It shows the method based on response spectrum can predict the failure state of structure more simply and accurately.(2)The casualties and economic losses are used as indicators to measure the losses under regional earthquakes,and the regional building information is investigated to determine the damage state of buildings under earthquakes with different intensities.According to the corresponding relationship between casualties,economic losses and structural damage degree,the regional casualties and economic losses are assessed.The cost and personnel distribution of various buildings in the region are analyzed and investigated,then the losses under the regional earthquake can be calculated.It provides a quantitative reference for the post-earthquake disaster relief command and rescue plan.(3)Based on the influence of earthquake on the evacuation process,the microscopic characteristics of evacuation under earthquake are analyzed.Through multi-agent model and social force model,dynamic evacuation simulation based on the shortest path in the region iscompleted,and the autonomous behavior of evacuees in micro-level is well considered.The regional evacuation was analyzed from the perspective of evacuees,and the regional evacuation process under small earthquake,large earthquake and mega earthquake was simulated.In the existing regional planning,the evacuation results are compared by adjusting the width of the entrance to the refuge area,so the optimal width of the entrance to the refuge area is obtained,which improves the efficiency and safety of regional evacuation.In addition,the number of people in the dangerous area with time was monitored,and the danger degree of regional evacuation under different conditions was compared with the danger coefficient.