Research On Dynamic Analysis Model And Evaluation Method Of Urban Resilience

With the acceleration of urbanization,cities are often damaged by many traditional and new disaster events,such as subway tunnel fire,urban floods,and network information security incidents.Improving urban resilience is an important way to ensure urban security in the new era.Taking "theoretical analysis-model construction-parametric analysis-practical application" as the main line,this paper deeply analyzes the connotation,characteristics,main influencing factors,and laws of urban resilience.Based on the above analysis,a dynamic analysis model for urban resilience and a comprehensive assessment method for urban resilience are proposed.The research work of this paper can provide theoretical and methodological reference for the construction and evaluation of urban resilience.The main conclusions are as follows.(1)The relevant concepts,characteristics,main theoretical support and long-term and short-term changes of urban resilience are discussed.At the same time,a conceptual framework for the application of urban resilience theories and methods to practice is explored.Urban resilience,with characteristics such as robustness,recoverability,adaptability,develops continuously under the support of basic theories such as complex adaptive systems.In the short term,urban resilience has different evolutionary performances in single-hazard scenarios,multi-hazard(sequential and concurrent)scenarios,different restoration scenarios,and urban-related system scenarios.In the long run,the evolution of urban resilience is affected by many factors such as the city’s environment,the frequency of disasters,and the maintenance of managers.(2)On the basis of analyzing the mechanism of urban resilience,a comprehensive evaluation model and method of urban resilience based on resilience curve are proposed.Urban resilience can be divided into urban engineering resilience and evolution resilience.Urban systems rely primarily on their own engineering resilience to respond to known disasters within their capabilities.Then urban evolution resilience comes into play.During the long-term development of cities,the urban system’s ability to respond to unknown disasters and super-record disasters will be improved,with the continuous accumulation of disaster response experience under the influence of adaptability and the continuous optimization of urban system resilience and resilience.The proposed comprehensive evaluation model of urban resilience is a comprehensive evaluation of urban engineering resilience and evolution resilience,and can provide new ideas for solving the problem of misjudgment in special scenarios.(3)After analyzing the change mechanism of urban system performance under disaster scenarios,a dynamic analysis model of urban resilience based on system performance evolution is established.Based on the established model,the impact of three key factors(urban resistance,restoration and adaptability)on urban engineering resilience,evolutionary resilience and comprehensive resilience are analyzed.Meanwhile,the interaction mechanism between these factors is also discussed.The parametric analysis results are as follows.Urban resilience is directly affected by resistance,through the ability of cities to withstand disasters.Urban resilience is directly impacted by restoring,through the time it takes to recover from a disaster.Urban resilience is indirectly affected by adaptability,through optimizing resistance and restoring after disasters.In the long-term response to various disasters,the urban resistance and restoration can be optimized with the promotion of adaptability,after the urban system encounters a specific level of disaster.Correspondingly,urban engineering resilience,evolution resilience and comprehensive resilience can also be improved.There are several possible characteristics of the interaction mechanism between urban resistance,restoration and adaptability.First,as the initial value of urban resistance increases,the improvement space for urban resistance and restoration will gradually shrink,and the rate of urban resilience will gradually decrease,and the rate of urban resilience improvement will also gradually decrease.Second,increasing the initial value of urban restoration may not contribute to the improvement of urban resistance and adaptability.Third,the increase in the initial value of urban adaptability has a certain effect on improving the rate of urban resistance and restoration.The proposed dynamic analysis model of urban resilience can provide a research foundation for further exploring the changing laws of urban resilience.(4)Through the analysis and discussion of the characteristics and main differences of different disaster scenarios,an analysis model for the evolution law of urban engineering resilience under disaster scenarios is constructed.According to the established model,the evolution law of urban engineering resilience under transient and continuous single-hazard scenarios and some scenarios where multiple disasters occur in succession is studied.Research shows that there are similarities and differences in the evolution of urban engineering resilience under these scenarios.The same point is that,within a certain range,increasing the parameter value of a single factor has different degrees of promoting effect on optimizing the resilience of urban engineering.The difference is that in a scenario with only one disaster,improving resilience alone will not reduce the direct losses suffered by the urban system,but this reduction effect may be effective in a scenario where multiple disasters occur in succession.Under the same conditions as parameter increase,number of disasters and maximum intensity of disasters,the upper limit value of urban engineering resilience optimization under continuous single disaster scenarios is lower than that of instantaneous single disaster scenarios in most cases.(5)In the field of urban transportation system,the practical application of the comprehensive assessment method of urban resilience is carried out.Specifically,take subway train running safety resilience as an example.Taking the emotional stability of subway passengers as the subway service performance index,and combining with the constructed resilience evaluation model,the resilience of the MTR East Rail Line from2007 to 2009 is evaluated for safe operation of subway trains.The results show that the comprehensive resilience level of the safe operation of the trains on the Eastern Rail Line of the MTR from 2007 to 2009 is intermediate.However,it is gratifying that the resilience value is increasing year by year,and it is close to a higher level.The conclusions obtained in this paper can provide a theoretical reference for urban resilience optimization.Concurrently,these conclusions can also have certain guiding significance for the resilience evaluation of urban fire safety,urban infrastructure and other actual scenes.This article contains 159 figures,45 tables,and 158 references.