Research On The Spatial Pattern And Change Of China's High-speed Railway Network

China's high-speed rail network has taken shape,growing in scale and coverage,with the implementation of "the mid-long term planning for China's railway network".The network development of high-speed railway is helpful to improve passenger service,optimize spatial pattern and promote economic development.Abundant research achievements have been made on the socio-economic impact of high-speed rail.However,there are few researches on the spatial pattern characteristics of the high-speed railway network,which need to be further deepened and expanded.Based on the theory of social network analysis and the theory of regional spatial structure,this paper analyzes the spatial pattern characteristics and temporal and spatial evolution of China's high-speed railway network from three aspects.First,study the spatial pattern characteristics of high-speed railway network by individual actor,local area network and whole network.Second,the evolution model of China's high-speed rail network is refined and summarized.Thirdly,the driving factors of the evolution of high-speed railway network are studied by combining theory with empirical analysis.The conclusions are as follows:(1)Timing changes of node centrality and accessibility.From 2014 to 2019,With the development of high-speed railway network,the centrality of node cities has been improved as a whole from 2014 to 2019.However,the mediating degree changes little and is generally low,and the network connection is highly dependent on some nodes.The temporal changes of node function and status reshape the spatial pattern of the network.The network pattern dominated by a small number of eastern cities has been changed to the trend of multi-center and balanced development.High-speed railway improves the accessibility of cities along the route,but it has obvious "corridor effect".In recent years,the spatial gap of accessibility has been gradually narrowed,and the spatial continuity has been improved year by year,which reflects the characteristics of considering regional fairness in China's high-speed railway construction.(2)Formation and evolution of high-speed railway Economic circle.High-speed railway weakens the constraint of geographical distance on urban connection,brings space-time compression and urban integration effect,and promotes the formation and development of high-speed railway economic circle.he 2H economic circle has experienced the evolution of spatial form from local agglomeration to trunk line series and then to sheet continuous stretch.The connection strength within the 2h economic circle is significantly improved and the connection structure tends to be complex.The4 h economic circle is mainly centered on provincial capitals.With the expansion of high-speed railway network and the improvement of operation service,the influence scope of central city is constantly expanding,but the connection intensity shows the characteristic of decreasing circle level.(3)Characteristics and evolution process of network macroscopic pattern.China's high-speed rail network is expanding from east to west on the whole,with larger scale and higher density,but it is still in a weak connection state.The network density has obvious spatial difference,showing the characteristics of "eastern >,central > and western >".The complex network pattern on the national scale replaces the axial belt pattern on the regional scale,and corresponds to the "eight vertical and eight horizontal" network as a whole.The addition of regional and intercity lines has significantly improved network connectivity.In addition,the high-speed rail passenger connection also has an obvious distance attenuation effect,generally showing an inverted "U" shape,while the number of trains running between cities shows an inverted "V" shape.(4)The evolution pattern of high-speed railway network pattern.The pattern of China's high-speed railway network has changed greatly in recent years,which can be divided into three development stages.In 2014 and before,the national network was in the stage of development.At this time,the local network was mostly polar core mode,and the national network was mainly expanded along high-speed railway trunk lines.The high-speed rail network expanded steadily from 2015 to 2016.With the comprehensive penetration of the network framework,the network gradually formed a beaded pattern Starting in 2017,China's high-speed rail network entered a boom phase.The main network,regional network and intercity network intersect and overlap.(5)The driving factors of the evolution of high-speed rail network pattern.The results show that the evolution of China's high-speed rail network is mainly influenced by the level of economic development,population size,urban administrative functions and strategic planning.The administrative function and local planning can promote the network construction and structure improvement,and the degree of influence has been improved in recent years.However,the level of economic development,population scale and income level have an inhibitory effect on the network pattern.The larger the gap between cities,the more unfavorable the establishment of close ties.In addition,in the stage of network development,the influence of industrial structure is not significant.With the development of network,the inhibitory effect of industrial structure increases.The countermeasures and Suggestions are as follows.First,with the stable spatial layout of high-speed railway network facilities,the improvement of operation service will become the key to improve the network operation efficiency.Second,regions with developed high-speed rail networks should avoid excessive expansion,pay attention to improving the connectivity of high-speed rail with various transportation systems.Third,it is necessary to appropriately promote the construction of high-speed railways in the western region and solve the problem of unreasonable layout of facilities.The innovation of this paper is as follows.First,it makes a comprehensive and systematic analysis of the spatial pattern characteristics and temporal and spatial evolution trend of China's high-speed rail network,which makes up for the existing deficiencies.Second,the evolution patterns of China's high-speed rail network are summarized and refined,which are polar core pattern,axial belt extension pattern,bead pattern and multi-center network pattern respectively.Third,the empirical analysis using QAP concludes that administrative hierarchy and strategic planning are the main factors to promote the development and improvement of China's high-speed rail network,while economic development level,population size,income level and industrial structure have inhibitory effects.Fourthly,web crawler and programming are used to fully mine and sort out the data,providing rich materials for th e follow-up research.There are 28 figures,20 tables and 187 references.