Research On Site Selection And Transport Network Optimization Of CHINA RAILWAY Express Assembly Center Under Carbon Constraints

CHINA RAILWAY Express is a key construction project in the "the belt and road initiative" initiative,which has been developing rapidly since its inception.With the increase of the overall transport capacity of CHINA RAILWAY Express,such as duplication of routes and vicious competition of goods supply,the transport efficiency of CHINA RAILWAY Express decreases and the traffic resources are wasted,which greatly hinders the development of China-Europe trains.Therefore,start to solve the current predicament and realize the normal operation of all trains in China and Europe at an early date.Specifically,the following studies are made to solve the above problem :This thesis takes the outbound domestic section of the CHINA RAILWAY Express as the main research object,and studies the layout of the logistics network and the optimization of the transportation network of the CHINA RAILWAY Express in China.First,based on the 68 cities where CHINA RAILWAY Express operate in China,taking into account the dual factors of the city’s own logistics level and inter-city logistics links,the CHINA RAILWAY Express assembly centers are determined by constructing a two-tier planning model,including Shenzhen,Chongqing,Xi’an,Zhengzhou,Tianjin,Dalian,Urumqi and Suzhou.Among them,by constructing the urban comprehensive logistics development level index system,the entropy weight-TOPSIS model is used to evaluate the urban comprehensive logistics level,and the inter-city logistics connection is measured by improving the gravity model.Based on the determined CHINA RAILWAY Express assembly center,the radiation range of the assembly center is determined by the membership degree model calculation,and the hub-and-spoke logistics network of the CHINA RAILWAY Express is constructed with the railway as the trunk line channel between the assembly centers and the assembly center and other operating cities as the branch channel of public and railway intermodal transport,and the cargo transit and assembly mode of "operating city-assembly center-port" is used as a supplement and improvement of the point-to-point direct mode of operation.Second,on the basis of hub-and-spoke logistics network,combined with multi-objective optimization theory and carbon emission theory,the current optimization problem of CHINA RAILWAY Express transportation route selection is analyzed,taking into account the economic and environmental benefits of CHINA RAILWAY Express n operation.Based on different modes of transportation and different means of transportation,logistics costs include transportation costs,transit costs and miscellaneous costs,and carbon emission calculations include carbon emissions from road transport,emissions from railway transport and carbon emissions from transit transport.Finally,a dual-objective optimization model with the lowest cost and carbon emission of integrated logistics for container-bus-rail intermodal transport is constructed.Based on the constructed dual-objective optimization model,it is solved by NSGA-II algorithm.The third is case analysis.The case analysis of the multi-objective optimization model is made by selecting the actual transportation data of CHINA RAILWAY Express from ARE company.The results show that the operation efficiency of CHINA RAILWAY Express based on the transit-assembly mode of "opening city-assembly center-port" can not only greatly reduce the logistics cost,but also significantly reduce the carbon emissions generated during transportation compared with the direct transportation mode,which is of great significance to promote the coordinated development of economic benefits and environmental benefits.