Study On The Circle Line In The Network Planning Of Urban Rail Transit

Facing the contradiction between rapid economic growth and the vast resource depletion and ecological damage, the sustainable development requests that environmental protection and resource usage will value more in urban development. Because of the characteristic of less consumption, less pollution, safety and comfort etc, Urban rail transit is then of great significance for improving urban environment and promoting city sustainable development.The study in the process of network planning and revision has focused on functional analysis, setting condition, setting scale and other related problems of circle line of urban rail transit. Clear understanding of these problems will prevent circle lines from unreasonable setting, which might keep the circle line from full function. Therefore, it is necessary to study on the problems of functional analysis, setting conditions and scale to provide a reference for the circle line planning.Based on analyzing the influence factors of urban rail transit network planning scheme, factors including the urban land-use scales, urban layouts (urban land use structure), level of economic development, size of urban population, scale of road net, urban development strategy, and scale of urban railway transit network are analyzed. And combined with urban transit construction in some cities, it is concluded that the main factors are urban layouts, urban development strategy, scale of passenger flow and urban railway transit. By meeting the basic conditions of urban rail transit construction for premise, the construction conditions of circle line are analyzed from three aspects as urban layouts, scale of passenger flow and urban railway transit. After analyzing the pre-existing evaluation systems of urban rail transit network in our country and also the influence factors and setting conditions, this paper establishes an evaluation indices system to compare the schemes of circle and no-circle. By using the method of the fuzzy analytic hierarchy process (F-AHP) to get the index weight and based on the idea of principal component analysis (PCA), the paper proposes the evaluation model of PCA with weighted variables. Finally, an example is used to verify the influence factors, setting conditions and the evaluation model.