Study On The Construction And Optimization Of High-speed Railway Network In Shaanxi Province From The Perspective Of Accessibility

As a national key infrastructure and major livelihood project,the construction and development of high-speed railway has a sustained and far-reaching impact on China’s urban and regional spatial organization.Shaanxi Province as an important transportation hub in Northwest China,will focus on the construction of "meter" shaped high-speed railway network during the 13th Five Year Plan period to speed up the integration of high-speed railway network The national "eight vertical and eight horizontal" high-speed railway network will realize the smooth operation of high-speed railways with the surrounding provincial capitals.After the completion of the network,the status of Shaanxi as a transportation hub will be further strengthened nationwide.This paper takes Shaanxi high-speed railway transportation network as the research object,which is divided into four research scenarios:the initial stage of construction(2015),the current construction period(2020),the construction planning period(2030)and the construction optimization period.Based on the in-depth analysis of the development process and spatial pattern of the high-speed railway network,from the perspective of the spatial change of traffic accessibility caused by high-speed railway,the shortest travel time is adopted This paper studies the accessibility impact of high-speed railway construction on three spatial scales of Shaanxi Province,prefecture level cities and counties under the above research scenarios by four evaluation indexes:time,weighted average travel time,daily accessibility and accessibility coefficient.Secondly,the economic gravity model is constructed to study the influence of high-speed railway construction on the urban economic connection strength and urban spatial interaction in Shaanxi Province from 2015 to 2030,and to clarify the change of urban economic connection pattern caused by high-speed railway construction.Finally,from the perspective of project management,this paper puts forward corresponding suggestions on the construction and planning of high-speed railway project in Shaanxi Province,so as to better serve the industrial structure adjustment and economic growth of Shaanxi Province.The main conclusions are as follows:(1)From 2015 to 2020,the density of ordinary passenger railway increased by 12.80%,and the density of high-speed railway increased by 186.40%.From 2020 to 2030,the density of ordinary passenger railway in Shaanxi Province will increase by 25.60%and that of high-speed railway by 94.40%.There is a big gap in the development level of high-speed railway construction in Guanzhong,Northern Shaanxi and Southern Shaanxi.The weighted road network density in northern Shaanxi is the lowest.The weighted road network density was 61%of the province’s average level in 2015.The distribution of traffic network shows the spatial differentiation characteristics of dense in Guanzhong area and sparse in Southern and Northern Shaanxi.(2)From 2015 to 2020,the average shortest travel time of all prefecture-level cities in Shaanxi Province decreased to varying degrees.The shortest travel time from Hanzhong City to Yan ’an City shortened by 2.92 h at most,indicating that the construction and opening of high-speed railway can significantly improve the accessibility of cities with less developed transportation.In five years,the maximum shortest travel time from Xi ’an to the whole province was reduced from 9.45 h to 8.26 h.The average accessibility index of Hanzhong city decreased by 1.71 h,Yan’an city decreased by 0.84 h,Yulin city decreased by 0.78 h,and the reduction values of other cities were all within 0.40 h,indicating the marginal effect of high-speed railway construction.(3)The daily accessibility circle extends from the administrative center of prefecture level cities to the periphery along the railway and high-speed railway lines,and the expansion direction is highly coincident with the extension direction of high-speed railway.The effect of high-speed railway construction and development on the daily accessibility of different time layers is different.With the extension of time,the effect intensity first increases and then decreases,and the effect on the change of 4 h daily accessibility range is the most significant.(4)Under the scenario of high-speed railway construction planning in 2030,the impact of high-speed railway construction on accessibility is no longer limited to the cities along the route,but improves the weighted average travel time of the whole province as a whole,and the planned high-speed railway line changes the relatively isolated form of Yulin City and Ankang City.After the optimization of high-speed railway construction,the gap between the edge cities and the traditional cities with developed transportation has been shortened.Most areas in the province can reach within 4 hours,and the accessibility of Guanzhong area is still better than that of southern and Northern Shaanxi.Xi’an,the capital of the province,can commute within 7 hours,and its core position has been consolidated.(5)Under the three time scenarios of 2015,2020 and 2030,the intensity of economic ties among prefecture level cities in Shaanxi province continues to increase,and the pattern change of economic ties intensity is closely related to the construction of high-speed railway.From the total amount of foreign economic ties of prefecture level cities,the intensity of foreign economic ties of Xi’an and Xianyang is significantly higher than that of other cities,and the radiation driving effect of Guanzhong core area is significant.(6)In view of the regional differences in the three regions of Northern Shaanxi,Guanzhong and Southern Shaanxi,suggestions for the development of future high-speed railways are put forward.In Northern Shaanxi,we should accelerate the construction of high-speed railway network,promote economic circulation,develop characteristic "red tourism";Guanzhong should develop a multi-center organizational structure of urban networks,and strengthen the connection and combined development of high-speed railways and other means of transportation;Southern Shaanxi should increase The density of the high-speed railway network must be fully considered in southern Shaanxi’s regional economic development level and resource and environmental conditions to better explore diversified industries and avoid the loss of production factors such as human,property and material caused by "siphon effect".