Research On The Development Of The Fringe Of Megacity Under The Influence Of Suburban Line Of Rail Transit

The urban fringe area,as an important area for the expansion and function transfer of large cities,is the most complex and sensitive zone for the nature of land use,population and economic attributes,and functional space.At the same time,the construction of rail transit is rapidly carried out in large cities,and it is increasingly important to strengthen the coupling of transportation and urban space.For urban fringe areas,rail transit has promoted the evacuation of population from the core area,bringing a certain degree of development opportunities along the route,but at the same time,due to the bidirectional flow,the fringe areas are also facing the core area in the functional development Competitive pressure.Therefore,studying the influence of rail transit suburban lines on the fringe areas is an important content for exploring the orderly development of fringe areas and guiding the rational layout of urban space.This study is based on the analysis of the relevant theories of suburban development and transportation systems in megacities at home and abroad,and the summary of case experience.Beijing edge area is selected as the research object,using accessibility evaluation,spatial kernel density,average center calculation,cold hot spot distribution calculation,etc.Methods: Obtain the development characteristics of traffic,population,function and land use in the fringe of Beijing.Combining the relevant planning,laws and regulations of Beijing and the investment and operation mode of rail transit,planning strategies for different areas along the macro,meso and micro lines are proposed.The analysis results show that: the opening of rail transit lines improves the overall accessibility of the city,the connection between the fringe area and the core area is enhanced,but the connection between the fringe areas is weak.The golden period of land development along the line is about 5 years before the line is approved and opened.Among them,the change within 1km is the most sensitive,and the most significant change is the residential function from the village construction land.The service function in the urban function has a tendency to move to the marginal area to a certain extent,but the core business and business functions are still slightly expanded within the original core area,and the "single core" feature of the economic production level has intensified.The accumulation of permanent population in the marginal area and the transfer of industrial functions have produced a certain time difference.The phenomenon of "segregation of work and residence" is obvious,and a large amount of commuter traffic between the core area and the marginal area has been generated,which has become the driving force for the development of suburban lines and Passenger flow support.In the long run,the comprehensive development of the functions of the marginal zone is the effective measure for the marginal zone to truly relieve the population and functions of the core zone and share the pressure in the core zone.The urban spatial structure should be rationally combined with the rail transit skeleton and urban planning policy guidance,and the E-TOD mode development should be carried out with the periphery area,especially the new city center,as the catalyst,and around the site.Based on the development advantages of science and education,residence,innovative industries or international exchanges in different regions,the peripheral area and the core area will be integrated at the municipal level,and the connection between the edge areas will be strengthened to create a "secondary network" structure to change The unidirectional attraction of the core area to the marginal area ultimately optimizes the "single core" structure to achieve balanced development.