The Impact Of High-speed Rail On Accessibility And Economic Relationship Pattern Of Urban Agglomeration In Guanzhong Plain

High-speed rail is a new type of transportation featuring high speed and large volume.The launch of high-speed rail can greatly reduce the travel time along the line,and brings about a "space-time contraction" effect so as to speed up the flow of personnel,information,capital and other factors,promote the economic development in areas along the line and restructure the relationship pattern of regional economy.China's development has entered a new era whereby the Guanzhong Plain urban agglomeration usher in new advance opportunities.In early 2018,the State Council approved the "Guanzhong Plains Urban Agglomeration Development Plan",and the construction of the "?"-shaped high-speed rail network gained the strong support from the central government.The study of the impact of the "?"-shaped high-speed rail network on the accessibility of the urban agglomeration and on the economic relationship pattern has a great significance to optimize the construction of urban railway network,promote the rapid development of the urban agglomeration,and accelerate the construction of the national central cities of Xi'an.This paper takes 11 prefecture-level cities in the Guanzhong Plain urban agglomeration as the research object.Based on the regional and inter-regional perspectives,it selects three time points,concluding 2006(before the launch of the high-speed railway),2017(the status quo of high-speed rail operation),and 2025(After the completion of the "?"-shaped high-speed railway network),and three time periods of 2006-2017(no high-speed rail-status quo),2017-2025(the status quo-"?"-shaped high-speed rail network completed),2006-2025(no high-speed rail-"?"-shaped high-speed rail network Built)whereby constructs evaluation indicators relevant to accessibility and economic relationship pattern,and analyses the impact of high-speed rail on urban agglomeration and economic relationship pattern.The results show that:(1)After the opening of the high-speed railway,the accessibilit within the urban agglomeration and inter-regional areas will increase rapidly;the difference in accessibility between the cities along the high-speed railway and the cities along the Normal-Speed Train will be expanded;the spatial and temporal differences in accessibility levels between cities at different levels will be observed.Obviously,it has a "core-edge"spatial pattern;the improvement of accessibility between cities at different levels is different,and the opening of high-speed rail significantly improves the accessibility level of newly opened high-speed rail cities.(2)After the completion of the high-speed railway,the economic potential of urban agglomerations and inter-regional areas will increase rapidly;the economic potential of cities at different levels will be significantly different in time and space,and the economic potential pattern will be "core-edge";the opening of high-speed railway will widen the gap between cities.,creating a "siphon effect";high-speed rail construction can quickly increase the economic potential of cities along the line,especially in marginal areas.(3)After the completion of the "?"-shaped high-speed rail network,the "2h exchange circle" and the inter-regional "4h exchange circle" in Xi'an urban area expanded rapidly,and the radiation range was greatly expanded,which will help the construction of Xi'an national central city.(4)After the completion of the "?"-shaped high-speed rail network,the economic linkages between cities increased substantially and the integration process of Xian and Xianyang accelerated.The "?"-shaped high-speed rail economic belt of urban agglomerations was formed,forming an economic relationship pattern of "one circle,one axis,three belts".