| With the development of economy and society,the demand for residents’ travel and cargo transportation has increased significantly,and the stability of highway network traffic performance is crucial.In recent years,extreme weather has occurred frequently,meteorological and geological disasters have threatened the stable operation of the highway network,and traffic accidents and traffic congestion have also brought severe challenges to the smooth operation of the highway network.Many scholars use the theory of complex networks to analyze the invulnerability of the traffic network from the perspective of topological geometry,but ignore the traffic characteristics of the traffic network itself.Based on the research of network invulnerability,combined with complex network theory and traffic characteristics,this paper constructs a highway network network model from two levels of network extension structure and regional traffic distribution,and analyzes the characteristics of the highway network;analyzes the highway from unilateral failure and multilateral failure Network invulnerability;construct a invulnerability optimization model,and obtain a new highway plan through improved genetic algorithm.This article takes the highway network of Boluo County,Guangdong Province as an example to demonstrate.Research helps highway management departments understand the vulnerability of highway network and provides effective planning basis for highway network planning.The specific research work of this article includes:(1)Analysis of the characteristics of the highway network.On the basis of the traditional network topology model,this paper combines the traffic distribution model to construct a two-layer model of the highway network.Analyzing the characteristics of the highway network from the degree,shortest path,agglomeration coefficient and betweenness,it is concluded that the highway network of Boluo County does not have the characteristics of small world,nor does it have the characteristics of scale-free.(2)Evaluation method of highway network invulnerability.Three network geometric indicators,namely,the global efficiency of the network,the proportion of reachable nodes,and the largest connected subgraph are selected,and the invulnerability is evaluated from the three perspectives of node connectivity efficiency,network reachability,and network connectivity.At the same time,comprehensive topological structure and traffic demand,the network OD weighted efficiency index is proposed,which provides a new angle of traffic operation and highway network traffic performance for the evaluation of the invulnerability of the highway network.(3)Identification of key sections of highway network based on unilateral failure simulation.Through unilateral failure simulation,the key sections of the highway network are identified based on the traffic performance of the highway network.The results show that the impact of key sections on the traffic operation of the highway network is 8.74%～6.13%.(4)Analysis of the invulnerability of the highway network based on multilateral failure simulation.Through multilateral failure simulation,it is obtained that the invulnerability of highway network under deliberate attack is weaker than that under random attack.The results show that traffic performance and network accessibility under random attacks are the most affected,followed by node connectivity efficiency and network connectivity;traffic performance and network accessibility under deliberate attacks are affected the most,followed by network connectivity and node connectivity efficiency.(5)Optimal method of highway network invulnerability considering traffic distribution.The highway network invulnerability optimization model is constructed with the highway network traffic performance as the optimization goal,and the three constraints of the new highway budget,two-way traffic and the maximum highway mileage are determined,and the highway network highway construction plan is obtained through an improved genetic algorithm.The results show that under random attacks and deliberate attacks,the traffic performance of the highway network is increased by 42.91% and 219.26%,respectively,which is better than the optimization effect of the traditional network plus edge optimization strategy.This paper proposes an optimization method that can significantly improve the invulnerability of the highway network. |
