Study On The Influence Of Urban Road Network On The Layout Of Subway Network Planning

In recent years,China’s rapid economic development has accelerated the pace of urbanization,and one of its notable features is the vigorous development of urban rail transit represented by subway.Line network planning is an important part of whole life cycle of the subway construction and key prophase work.For a long time,although the domestic and foreign scholars did many detailed and comprehensive research on the morphology and the structural properties of the subway network and the urban road network,but few of the research combines these two networks together and studies the relationship and influence between them.In the actual situation,the subway network and the urban road network has many associations.Most of the main subway lines lay along the urban expressway,the main road and other important traffic corridor In addition,these two networks are connected in terms of their form layout and the structure.As a result,it is necessary that the influence of urban road network is studied and analyzed as an important reference during the online network planning and optimization process.This paper sorts out the policy requirements,planning points and compilation process of subway network planning,clarifies the special relationship between subway network planning and other related planning,and deeply analyzes the influence of urban road network on each stage of compilation process of subway network planning.This paper qualitatively describes the correlation between the two kinds of transportation networks based on typical urban cases at home and abroad and the relevant data in these cases.On this basis,the paper deeply explores the influence of urban road network on the route direction,site accessibility and extension of subway line network from three perspectives of "line","point" and "overall layout".Along this train of thought,this paper proposes the allometric growth relation model of urban road network and the subway network based on the fractal theory.After obtaining the values of the network-radius dimension and the node-radius dimension of these two kinds of networks,we use the fractal dimension consistency,the vector similarity as well as the allometric growth scale for quantifying the coordination and the relevance between the subway network and the urban road network in the process of growth.Finally,taking Cheng Du metro network and urban network in operation as the research object,the allometric relationship between Cheng Du metro network and urban network as well as the correlation and coordination between the two transportation networks are obtained based on the above mathematical model for example analysis,so as to determine the influence of urban network on the layout of subway network planning.