Spatial structure of urban agglomeration under the impact of high-speed railway construction: Based on the social network analysis

As a typical mode of modern transportation, high-speed rail (HSR) plays a key role in the formation and development of today's regional spatial pattern. Based on the panel data of 2009, 2012, 2015 and 2018, Beijing-Tianjin-Hebei Urban Agglomeration is taken as the research object and the social network analysis method is used by this research to explore the evolution of urban agglomeration spatial structure under the impact of HSR construction. The results show that Firstly, HSR construction increases the average network density of urban agglomeration by 0.0487, which promotes the spatial connection density of urban agglomeration in a positive way. Secondly, HSR can improve the point centrality of moderately developed cities by 0.87, reduce the spatial connection of urban agglomeration' dependence on core cities, and improve the urban agglomeration' stability of spatial structure. Thirdly, HSR can make more cities enter the core subgroup faster, and improve the speed of urban agglomeration evolution to the optimized state. Based on this, the following suggestions are put forward: first, cities without HSR should strengthen urban construction in order to achieve interconnection with cities with HSR as soon as possible. Second, HSR construction should be taken as an opportunity to cultivate new regional hub cities. Third, the transportation planning department should strive to improve the HSR construction level of the peripheral cities so that they can share the effect of HSR construction.