Research On Reliability Of Coal Transportation Highway Network In Shaanxi Province

Today,coal resources have played a crucial role in the development of the national economy.With the development of highways in China,the transportation industry has developed rapidly as well.The structure of coal transportation network in some coal producing provinces in China is becoming more and more complicated,and the stability of the network is affected by various internal factors as well as external factors.Internal factors refer to network faults caused by the network itself;external factors refer to network faults caused by natural disasters,serious traffic accidents,etc.,resulting in the failure of nodes or edges in the network,which will lead to coal transportation network congestion and increase of transportation time,meanwhile,the development of coal transportation industry is seriously affected,and the economic loss to coal chemical enterprises is also achieved to a certain extent.To ensure the normal operation of the coal transportation network,the reliability of the coal transportation network must be deeply studied.The purpose of this research is to help coal transportation enterprises to formulate reasonable transportation routes and at the same time to help decision makers identify vulnerable nodes and edges in the network and so that before the incident occurring,some corresponding protective measures can be taken to ensure the anti-damage ability of the networks.Model construction and characteristics analysis of coal transportation highway network.Based on the knowledge of complex network,the coal transportation network model is constructed.In this model,the coal origin,the transit,and the demand in the coal transportation system are abstracted as nodes of the network,and the transport lines between the nodes are abstracted as the edges of the network.The evaluation index of complex network is selected to analyze the static structure characteristics of coal transportation network from the aspects of distribution,clustering coefficient,average path length and medium number.The coal transportation highway network belongs to the scale-free network,that is,the degree of most nodes is relatively low,and only a few nodes are relative high.At the same time,it can be found that the network has heterogeneity,that is,the nodes with large size tend to connect with nodes with medium size.Study on static reliability simulation of coal transportation highway network.Aiming at the problem of coal transportation highway network blockage caused by the destruction of nodes or edges in the coal transportation highway network caused by emergencies,a network model built by duality method is esatablished based on the complex network theory,and its reliability is simulated and analyzed by MATLAB.To start with,the basic characteristics of the two networks are compared and analyzed,and then the relative variation of network efficiency is proposed to identify the key sections in the network.Based on this,the network reliability evaluation model is established,and three reliability evaluation indexes,namely network efficiency,relative size of maximum connected subgraph and network dispersion,are put forward.The result shows that the coal transportation highway network based on the original method and the dual method is robust to random attacks and vulnerable to deliberate attacks.Study on dynamic reliability of coal transportation highway network from cascade failure perspective.To research the reliability of coal transportation highway network in the case of cascading failure,a weighted undirected network model of coal transportation highway is constructed,and the importance of point strength analysis network nodes is proposed.The cascading failure model of coal transportation highway network is established.Based on this,an improved cascading failure model is put forward.The cascading failure reliability of the coal transportation road network is analyzed from four different destruction strategies,then two cascade failure indicators of network efficiency and cascading failure degree are proposed to analyse the effects of four different destruction strategies on the scale of network cascading failure.The research results show that the network cascading failure scale is closely related to the node capacity parameter,when the node capacity parameter is large,the network cascading failure scale is small,and vice versa;and the network cascading failure scale under the deliberate destruction mode is found to be larger than the random destruction mode.Through the research on the reliability of the coal transportation highway network in Shaanxi Province,the protection of the important node cities and transportation lines in the coal transportation road network should be strengthened in the future planning and operation,and the transportation efficiency of important nodes must be improved.It is necessary to optimize the network structure of coal transportation highways,coordinate the balance of failure resistance and economy of cascades.In order to share the load of important nodes,the load capacity of adjacent nodes can be appropriately increased.The governor must optimize network management methods and improve the management level of the network;at the same time,establish a rapid recovery emergency response mechanism for the failed node city,improve the information release mechanism and update the specific situation of the failed node city in time to provide reference for the transportation enterprises to change the transportation route.