Research On Seismic Resilince Assessment Method And Functionality Improvement Of Urban Road Traffic System

Urban resilience has become a major demand of the international community.With the increasing size of cities,how to effectively evaluate the functionality loss and long-term impact of potential earthquake disasters is particularly important for the development and construction of cities.The road traffic system is one of the most important infrastructure systems in modern city.After the occurrence of natural disasters such as earthquakes,maintaining the effective operation of road traffic system is critical for emergency rescue,evacuation,material transportation and reconstruction.Existing research on seismic resilience of road traffic system generally adopts the resilience indicator based on the integral value of functionality curve,but it cannot reflect the resilience ability in both earthquake resistance and rapid recovery,and there is a lack of phased post-earthquake functionality assessment method from the perspective of real urban traffic demand.In addition,the existing post-earthquake recovery decision models are unable to effectively compare the advantages and disadvantages of different strategies and have too high requirements for decision-makers,and the computational cost of functionality improvement decision models is too high when facing complex problems.To address the above issues,this paper makes an in-depth study of the seismic resilience assessment method and functionality improvement strategy of urban road traffic system,the main work is as follows:(1)According to the evolution of traffic demand,a multi-phase post-earthquake functionality analysis model of road traffic system is proposed.A multiple-parameter seismic resilience assessment method based on functionality loss and recovery time is developed,and a general seismic resilience assessment framework for road traffic system is established to provide the basis for engineering application.(2)According to the traffic behavior in the post-earthquake emergency phase of urban road traffic system,an emergency traffic demand matrix between affected nodes and emergency facility sets is defined,and a novel functionality indicator based on multiple-destination independent path algorithm is proposed.Additionality,the impact mechanism of road section damage on system functionality is studied,and a penalty-based method is established to evaluated the functionality loss of postearthquake road traffic system in the emergency phase.The rationality and accuracy of the proposed method in the emergency resilience assessment is verified by a numerical example.(3)According to the characteristics of simultaneous changes of traffic demand and network capacity in the post-earthquake recovery phase of urban road traffic system,a standardized post-earthquake functionality indicator based on weighted average traffic speed is proposed.The impact factors of system recovery are studied,and a three-indicator model is established to describe the post-earthquake recovery process.A general two-stage decision model for post-earthquake restoration of road traffic system is constructed to support the decisions on resource reserve and recovery plan.The applicability of the proposed method is illustrated by a numerical example.The proposed post-earthquake recovery decision model can fully traverse the solution space and obtain a set of non-dominant optimal solutions with different advantages,which can provide the decision-makers to consider also other preference factors and make a final choice.(4)An uncertain stochastic optimization model for post-earthquake functionality improvement decision of road traffic system is established.According to the principle of feature selection,an efficient alternative algorithm based on probabilistic joint importance is proposed.A numerical application is given to verify that the proposed method can provide a good approximation to the real optimal solution at a controllable computing cost and show good stability.(5)Taking a real well seismic fortified urban road traffic system in China as an example,the assessment results of its seismic resilience under different earthquake fortification levels are presented,and the reference target value for seismic resilience assessment is established,which provides a preliminary reference for the construction of seismic resilient road traffic system.