Research On The Inter City Railway Network Planning Of Beijing Tianjin Hebei Urban Agglomeration Based On The Urgency Of Planning

In the context of regional integration,China clearly proposes to promote the integration of national major regional strategies with the development of urban agglomerations,establish a new model of leading urban agglomerations with central cities and driving regional development with urban agglomerations,and promote the integration and interaction between regional plates.It is very important to build a comprehensive and efficient transportation system of urban agglomerations as a carrier of resource exchange and exchange within and between regions.As an important part of the comprehensive transportation system,intercity railway has outstanding advantages in horizontal selection due to its large transportation capacity,high speed,strong reliability and high density.Its scientific planning and layout of the line network can promote the evolution of the spatial structure of the urban agglomerations,guide the redistribution of the urban agglomerations,and have important strategic significance for the coordinated development of social and regional economy.First of all,the paper comprehensively analyzes the spatial evolution characteristics of urban agglomerations,the function and layout characteristics of intercity railway,and expounds the relationship between them,summarizes a variety of theoretical methods of line network planning,and analyzes their applicability.On the basis of the current mainstream layout of joint transportation location line based on the importance of nodes determined by social and economic factors,the paper considers that the location status of urban nodes in the current region should be included in the consideration of the starting point of urban agglomeration intercity railway network planning.Therefore,the concept of planning urgency is put forward in this paper,considering the accessibility of important urban nodes under the regional mixed railway network and the i-mportance of nodes based on social and economic factors.Secondly,using the distance measurement model,gravity model,complex network theory,spatial syntax and other models and theories,this paper focuses on the quantitative method of planning urgency of nodes and routes,establishes the calculation model of planning urgency,determines the principle of planning urgency as the node level division,and takes it as the planning starting point of this planning method.Then,taking Beijing Tianjin Hebei Urban Agglomeration as an example,using the above method,the planning urgency of 13 important urban nodes and intercity lines between nodes is calculated,and the planning priority of nodes is classified according to the above method.The results show that: Beijing and Tianjin are in the first urgency level because of their core position and prominent importance,and the quantified value of planning urgency is more than 1.5;Baoding,Shijiazhuang and Handan are in the second level,and the quantitative value of planning urgency is between 1.2 and 1.5,which indicates that the travel accessibility under the current railway network is difficult to match the node importance;Tangshan,Xingtai,Qinhuangdao,Zhangjiakou and Chengde are in the third level,and the quantitative value of planning urgency is between 1.0 and 1.2,and the node importance and travel accessibility performance are achieved Basically matching,but still reflecting a certain contradiction between railway supply and demand.Langfang,Cangzhou and Hengshui are at the end of the planning urgency level,and the quantitative value is less than 1.0,showing a certain advantage of railway location,and the importance is general,so the planning can be properly lagged behind;Finally,based on the above research results,the paper makes a reasonable improvement on the traditional line network planning ideas,and puts forward a method of urban agglomeration intercity railway network planning based on the urgency of related line network elements planning.Considering the hierarchical characteristics of the inter city railway network,aiming at the urgency of the planning of the selected nodes and routes,the route selection model and the primary route network planning model of the main skeleton network are established in turn,and the relevant model calculation method based on the improved aggregation algorithm is designed.Then taking the Beijing Tianjin Hebei Urban Agglomeration as an example,on the basis of the above quantitative results of the planning urgency of the nodes and lines of the Beijing Tianjin Hebei Urban Agglomeration,using the planning model of the inter city railway network of the urban agglomeration based on the planning urgency in this paper,the reasonable planning of the inter city railway network of the Beijing Tianjin Hebei Urban Agglomeration is carried out,and the final planning scheme is formed.The results show that the inter city railway network of Beijing Tianjin Hebei Urban Agglomeration Based on the urgency of planning has strong network characteristics and radiates around the core nodes,which is generally consistent with the urban spatial structure and economic development axis distribution of Beijing Tianjin Hebei Urban Agglomeration and the current situation of the existing mixed railway network.The planning results show that the planning method in this paper is realistic and reasonable,which embodies a considerable degree of feasibility and reference significance.The design of relevant models and algorithms can show a certain theoretical value and practical application value.