| With the rapid development of urbanization,the spatial layout of urban areas is gradually improved,and the population is growing and relatively concentrated.In the event of disasters,especially earthquake disasters with strong destructive power and wide influence range,the emergency safety issue of densely populated areas is particularly prominent.However,at present,there is still a lack of differential planning in the shelter space of urban areas,which easily leads to low overall evacuation efficiency and chaotic distribution of shelter in the process of emergency response after an earthquake disaster,greatly increasing the difficulty of disaster relief.Therefore,it is of great significance to carry out research on the planning and design methods of emergency congregate shelter spaces in urban areas and the allocation of post-disaster shelter resources to ensure the efficient evacuation and reasonable sheltering of disaster victims.In this paper,the central urban area of Xuchang City was selected as the research area,where the methods of personnel evacuation decision analysis and scenario simulation are adopted.Besides,a multi-agent-based emergency congregate shelter model for typical post-earthquake areas was established,and the optimal design methods for shelter space in different types of areas was proposed.Furthermore,the key resident emergency congregate shelters within the area were analyzed by the complex network theory.Then,considering the impact of the difference in the post-disaster recovery capacity of different areas on the post-disaster refugee demand,a dynamic simulation method of emergency congregate shelter demand was proposed,which can provide effective decision-making support for the allocation of post-earthquake urban shelter resource.The specific research contents are as follows:(1)The risk of disorderly evacuation of personnel in urban areas was analyzed.The information related to each functional site,resident emergency congregate shelters and evacuation road in the urban area was utilized to build a risk evaluation system for evacuation disorder in the area.Based on the percentage of functional land use,31 secondary disaster prevention zones in the central city of Xuchang was classified,and through evaluating each functional type area by SPA-VFRM,it is indicated that zones 17,5 and 23 among industrial,residential and integrated type areas were the typical areas with the most prominent risk of disorderly evacuation.(2)A simulation experiment on emergency congregate shelter of personnel in typical areas was carried out.Combined with the spatial characteristics of the resident emergency congregate shelters in areas and the demand for personnel refuge,an attractiveness assessment system of resident emergency congregate shelters was established.The subjective and objective combination weight-TOPSIS Method was used to calculate the attractiveness of each resident emergency congregate shelter in typical areas,and the Huff model was used to analyze the personnel evacuation behavior in each evacuation unit in the areas.Area evacuation space information is collected and processed,which would be imported into NetLogo platform to build an evacuation simulation environment,and a simulation experiment of typical area emergency congregate shelter considering the personnel disorderly evacuation was conducted.The results show that the evacuation time for areas 17,5 and 23 were 90,93 and 84 minutes,respectively,all of which exceeded the relevant code requirements.The service radius of resident emergency congregate shelters was further optimized,and the simulated results show that the overall emergency congregate shelter benefits of the areas were better when the service radius of resident emergency congregate shelters in industrial,residential and comprehensive areas were planned to be 2.0km,1.0km and 1.5km,respectively.Meanwhile,through adjusting the attractiveness of resident emergency congregate shelters in the area,reasonable evacuation guidance of evacuees can be realized.(3)A network model of emergency congregate shelter space for urban areas was analyzed and the change in refuge demand in the area was simulated.Firstly,the complex network theory was applied to establish a network model of emergency congregate shelter space in the urban area,and the key resident emergency congregate shelters would be determined by analyzing the characteristics of the nodes and overall network.In addition,NetLogo platform was used to carry out dynamic simulation of emergency congregate shelter demand,and the change of refuge demand in the area under the destruction scenarios of different sites based on the network characteristics was simulated.The results can provide scientific decision support for the post-earthquake area shelter management.Taken the personnel evacuation and sheltering in the emergency congregate shelter phase as the entry point,this paper has explored the optimization method of post-earthquake urban evacuation space from two scales of urban primary and secondary disaster prevention areas.The optimization method of emergency congregate shelter space has been proposed in terms of evacuation efficiency and resource crowding,and the influence mechanism of the spatial characteristics of urban disaster prevention zones and resident emergency congregate shelters on the personnel safe evacuation has been discussed.Considering the importance of the shelter and the need for personnel evacuation after the disaster,this paper can be helpful for providing strategic support to ensure the effective development of disaster relief work in the poster-disaster urban areas,and further enriching and deepening the theory of seismic disaster prevention planning and design in China. |
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