Research on compactness ratio model of urban underground space and compact development mechanism of rail transit station affected area

In order to assess the impact of underground space development on urban compactness, taking Shenzhen Futian Station and Tokyo Station as empirical cases, this paper uses the comprehensive compactness formula to extract influencing factors and to explore the interaction mechanism between underground space utilization and urban compact development. Previous studies have shown that when urban development reaches a certain threshold, the area compactness will be improved. Otherwise, when the development is below the threshold, the area compactness will be reduced. The compactness we discuss in this study is related to the efficiency of underground space development. The average building distance is a core factor affecting urban compactness and the efficiency of underground space development. Increasing total building area of underground space development of rail stations can significantly increase urban compactness.