关键词: 韧性城市, 冰雪天气, 路网恢复问题

Abstract: The winter snow and ice weather brings great impact on the urban road network traffic, which will seriously reduce the overall resilience of city. Because of the limits of emergency budget, the location and allocation of snow removal resources is highly correlated with the safety of urban traffic. Based on the perspective of the Resilient City,according to the historical winter weather data and road network structure in a certain city, how to optimize the layout of snow removal resources before snow weather and the plans of snow removal operations in different weather scenarios are studied, in order to improve the absorbing ability and recovering ability to extreme snow weather of urban road network.First, the average speed is used as the index of road network service capability and the Independent Pathway instead of all common pathway is taken as the evaluation target in the urban road network. Secondly, the whole wave process of road network is divided into two periods:absorbing period and recovering period. Accordingly, the metric resilience of urban road network can be expressed as:Res=((T_d-T₀)*(MOP_new-MOP_min))/(T_max-T₀)*(MOP₀-MOP_min), where T is the time index and MOP is service ability of the road network. Among them,(T_d-T₀) is the absorption period;(T_max-T₀) is the whole wave process of road network;(MOP_new-MOP_min) is the recovery value;(MOP₀-MOP_min) is the damage value. The four indexes are used to define the resilience (Res) of urban road network under snow and ice weather, which is set as the optimization target.A higher numerical value of the Res implies a strong resilience of road network. Thus, the LRP mathematical model is established based on optimization target. Third, the improved tabu search algorithm is designed based on the road classification. Last, the numerical analysis about the problem is made, thus, the following conclusions can be obtained. The resilience can systematically reflect the recovery process and can be set as the optimization target of road recovery under snow and ice weather. It is necessary to put the snow removal resources into the critical roads.The numerical result verifies the reliability of the model and method we processed. The study provides some management measures for road network restoration.

Key words: resilience, snow weather, road network recovery