Spatial Structure And Influencing Factors Of County-city Association Network Of High-speed Railway

By 2020,The length of China’s high-speed railways in operation will reach38,000 km,and 84.4% of the planned "eight horizontal and eight vertical" high-speed railway network has been completed and put into operation.The construction of the high-speed railway network is now basically in shape.The construct ion of high-speed railway has greatly promoted the evolution of China from traditional geographical space to flow space,and accelerated the flow of resources such as talents,capital,technology and information.Based on this,the Mid-and Long-term Railway Planning(2016-2030)further proposes a development vision: It is expected that by2030,the national high-speed railway network will basically cover counties,bringing new development opportunities to small and medium-sized counties along the route.However,most of the researches on high-speed railway network focus on prefecture-level cities and ignore the status and development status of small and medium-sized counties in the pattern of high-speed railway.Based on this,the analysis of the spatial pattern of China’s high-speed railway network at the county and city scale is helpful to clarify the achievements of phased high-speed railway construction,clarify the development status and network positioning of small and medium-sized counties in the high-speed railway network,so as to provide reference for the further improvement of high-speed railway network and the development of high-speed railway counties and cities.In this study,704 counties and cities with high-speed railway in China are taken as objects,and the association network of counties and cities based on high-speed railway train frequency data is constructed by using social network analysis method.Secondly,node index and network index in social network analysis are selected to analyze the hierarchical structure,spatial structure,overall network pattern and optimization strategy of high-speed railway network from the national and regional scales,and the geographical detector model is used to construct the influencing factors of high-speed railway accessibility in prefecture-level and above cities.The main conclusions are as follows:(1)At the national scale,the node level of high-speed rail network follows the pyramid structure of "provincial capital and deputy provincial cities-other prefecture-level cities-county-level cities" decreasing step by step.The country has formed a "point-axis" pattern with central cities as the core and "eight horizontal and eight vertical" main corridors as the axis.The Overall centrality of the Yangtze River Delta and the Pearl River Delta has become more regional,driving the relatively balanced development of neighboring counties and cities.(2)With the proximity of provinces as the main feature,the condensed subgroups expand along the high-speed railway corridor,forming the subgroups with the Yangtze River Delta,Pearl River Delta,central China,North China,northwest China,northeast China and southeast China as the core.The equilibrium of local networks was significantly different,the primacy linkage pattern showed significant spatial heterogeneity,and the maturation of regional networks promoted the integration process.(3)At the national scale,urban HSR accessibility is influenced by centrality and intermediary degree.Urban expansion,technological vitality,consumption level and urban function are powerful factors promoting HSR demand,while population,land,industrial structure and per capita GDP are limited.At the regional scale,economic construction indexes in North China,Yangtze River Delta and central China have the most significant promoting effect on urban high-speed railway construction.Different regions have different influence factors on high-speed railway construction,so it is necessary to analyze and formulate strategies to promote high-speed railway development according to local conditions.Research under the county scale based on the above conclusions,to depict the current situation of the development of China’s high-speed rail network,to provide high-speed network can be made use of research methods,has the theory significance,at the same time as the "eight vertical eight horizontal" and "ten transverse and longitudinal" long-term planning to provide practical reference,in order to promote further the balanced development of high-speed urban strategies and Suggestions.