Research On The Influence Of High-speed Railway On Accessibility And Economic Connection Strength In Southwest China

High-speed railway is an important means of production for social and economic construction in the new era.It occupies a key position in improving traditional railway transportation capacity,maintaining coordinated regional development,and supporting the strategic layout of national development.Although the national high-speed railway has achieved outstanding achievements under the support of national policies and funds,the problem of uneven and insufficient regional distribution is still significant.The mileage and the number of open-to-traffic cities of high-speed railways in the southwest are still at a lower level than those in the eastern and central regions.In the context of the era of high-speed railways,this paper uses 47 prefecture-level cities(prefectures)and above in the southwestern region of Sichuan Province,Yunnan Province,Guizhou Province,and Chongqing Municipality as the research unit,and focuses on growth pole theory and "point-axis" system theory.And on the basis of the core-edge theory,firstly,with the help of software Arc GIS 10.3,the basic data sets of the transportation network before and after the opening of the high-speed railway in the southwest region were constructed respectively.Secondly,through the O-D cost matrix,the shortest commuting time of cities in Southwestern China with or without high-speed railways is estimated.Thirdly,using the weighted average travel time,daily accessibility index,economic connection intensity and economic connection centrality and other evaluation index models,comparative analysis of the influence of the existing high-speed railways in the southwest region on the accessibility level and economic connection intensity of the cities in the region,And explore the evolutionary law of the two-space pattern.Finally,relevant countermeasures and suggestions are put forward for the economic and social development and transportation infrastructure construction in Southwest China.The research conclusions show that:(1)The opening and operation of high-speed railways promoted the improvement of the overall accessibility level in Southwest China.The gap in the accessibility levels of Sichuan Province,Guizhou Province,Yunnan Province and Chongqing City has gradually narrowed,and the weighted average travel time of different high-speed railway lines "corridor effect" The characteristics are obvious;the evolution of the spatial pattern of accessibility shows that the Chengdu-Chongqing urban agglomeration is the center and gradually weakens to the southwestern and northwestern marginal cities in the southwestern region;(2)The changes in the daily accessibility spatial pattern of the provincial capital cities have obvious traffic directionality,showing an axial and planar extension along the high-speed railway line.In the cities along the high-speed railway,the hourly economic circle of the cities along the line changes much more than the cities outside the line,and the degree of optimization of the daily accessibility of the cities outside the line is better than that of the cities along the edge of the region;(3)The economic connection intensity of cities in the southwest region shows the "Matthew effect".The total economic connection intensity of cities along the route has changed more than non-high-speed railway cities,and the economic connection intensity of transportation hub cities is higher than that of non-transport hub cities.,On the whole presents a "point-axis" spatial evolution pattern with Chengdu and Chongqing as the core points,Kunming and Guiyang as the secondary core points,and the high-speed railway line as the axis.(4)Chengdu and Chongqing have important core positions in the economic ties between cities in the southwestern region,while Kunming and Guiyang only have important positions in the economic ties between Yunnan and Guizhou provinces.The increase in economic centrality of cities along the high-speed rail is higher than that of non-high-speed rail cities.The radiation effect of central cities is strengthened,and the radiation effect of adjacent cities in central cities is weakened.