Research On Survivability And Node Redundancy Optimization Of Port And Hinterland Multimodal Transport Network

With the further deepening of economic globalization,the structure of the freight network is becoming more and more complex,and a single mode of transportation can no longer meet the diversified transportation needs of customers.With the continuous growth of maritime trade,it has become a hot spot for all parties to use containers to carry out the combined transportation of sea rail and public transport modes with seaports as the core.Multimodal transport has the characteristics of low transportation cost and flexible transportation mode.It can provide safe,accurate and personalized services for long-distance transportation of goods.In recent years,the high-quality development of the economy requires the infrastructure of the transportation network to have higher survivability,so as to resist the damage to the transportation network caused by emergencies.In January 2022,the COVID-19 epidemic broke out in Ningbo and Shenzhen.Although the local government and port companies took many measures,it still caused various levels of congestion in Ningbo-Zhoushan Port and Shenzhen Yantian Port.Therefore,the relatively backward infrastructure of the transport network and the uncertain factors of the regional environment are restricting the healthy development of multimodal transportation.The existing research on multimodal transport has not yet dealt with the cascading failure phenomenon and redundancy optimization of the multimodal transport network.Therefore,it is necessary to carry out the optimization of the survivability of the multimodal transport network and the redundancy of the network node capacity.This paper studies the survivability of transport networks and the optimization of node capacity redundancy in multimodal transport networks.First of all,based on the theory of complex network,this paper constructs the port-hinterland transport networks.By summarizing the cascading failure phenomenon of urban rail transit and other transportation networks,four types of network attack methods are summarized,and two network invulnerability evaluation indicators are selected.After that,according to the actual situation of the port-hinterland multimodal transport network nodes,a node importance evaluation index system is proposed,and the node importance is calculated to obtain nodes of different levels.The concept of node capacity is defined,and the network efficiency is evaluated according to the node capacity.The variation law of network efficiency is obtained Finally,taking a coastal province in northern China as an example,the survivability of transport networks in different modes is compared,the survivability of network nodes under different capacity redundancy coefficients is analyzed,and the impact of different redundancy coefficient combinations on the network is discussed.The effect of increasing invulnerability.The research results show that when the capacity redundancy coefficient of nodes is inversely proportional to the importance of nodes,the invulnerability of the network is significantly improved.When the redundancy coefficient is set to 0.8,0.9,1,the resistance probability is10.65%,which is higher than 4.7%,6.6% when the uniform redundancy coefficient is 0.8,0.9and 5.25% when the redundancy coefficient is set to 1,0.9,0.8,the optimization effect is close to that the redundancy coefficient is uniformly set to 1.The results of this study can guide the node planning,reconstruction and expansion of the port-hinterland multimodal transport network,and optimize the network node structure.It can improve the port-hinterland multimodal transport network survivability and improve port collection and distribution efficiency,and make construction more resilient.The developed port-hinterland multimodal transport network provides a certain theoretical basis and technical guidance to help build China into a country with strong transportation network.