Research On Reasonable Scale And Layout Planning Of Intercity Railway Network In Urban Agglomeration

City agglomeration is the product of the mature stage of urbanization development,the main form of new urbanization,and the organic integration of various elements in space.The efficient flow of production factors within city agglomeration is inseparable from the support of the integrated transportation system.As an indispensable part of the integrated transportation system,intercity railway has become an inevitable choice to meet the development needs of city agglomeration due to its advantages of fast speed,large transportation volume,safety,and energy-saving feature.In the development process of the intercity railway,how to avoid the blindness of the line network planning and construction,promote the sustainable development of the intercity railway,and truly play its leading role in the city agglomeration is a crucial issue.Seeking reasonable network scale and suitable network layout are the key to solving this problem.This paper conducts research on the reasonable network scale and layout of intercity railway network in city agglomeration.First of all,the basic concepts involved in the research object are clarified,and the relevant theories involved in the research content are explained,which lay the foundation for subsequent research.Secondly,the reasonable scale of intercity railway network is summarized.On the basis of summarizing the existing scale calculation methods of railway network,three suitable methods named connectivity method,load intensity method and analogy model are selected.Based on the limitations of a single method,a method of using entropy theory to calculate the network scale comprehensively is put forward.Thirdly,the intercity traffic location lines of city agglomeration are introduced based on the traffic location theory by analyzing the importance of nodes and the intensity of economic connections.Thereby a line candidate set is formed as the basis for the line network layout planning.The dual-objective planning model of the main skeleton of the network and the multiobjective planning model that generates the initial network plan using mathematical planning methods are establish to make a solution line in layers,and the solution algorithm is designed for the model,which realizes the quantitative generation of the network layout plan.At last,recommended network plan is generated on the basis of adjusting the initial network plan.Fourthly,this paper constructs a complex network based on the recommended scheme,and selects corresponding indicators to analyze its network characteristics and performance,so as to evaluate the adaptability of the recommended scheme.At last,taking the intercity railway of central Yunnan city agglomeration as an example,the method proposed in this paper is used for analysis.Combining the current situation and future development of the city agglomeration,the reasonable scale of the intercity railway network in the central Yunnan city agglomeration in 2035 is calculated to be 1988-2165 km.Compared with single method,the interpretation and operability of the results are significantly improved.MATLAB is used to solve the network layout planning model,and the results are adjusted to obtain the recommended network plan.Through comparative analysis and the use of Python to evaluate the adaptability of the network,the effectiveness of the method is verified.