基于空间句法实证分析的地下空铁换乘空间的步行可达性研究 — —以成都双流机场T2航站楼为例

空铁一体化发展使航站楼与城市铁 路交通便捷换乘成为必然要求，航空限高使 得空铁换乘空间多位于地下，多线换乘带来 的复杂换乘流线和地下空间带来的换乘空间 感知弱等问题导致空铁换乘效率低、舒适性 差，而换乘空间的步行可达性是影响换乘效 率和换乘舒适性的关键因素。成都双流机场 T2航站楼汇聚了空港、高铁、地铁等三种交通方式的换乘，通过研究该典型案例换乘空间的步行可达性来探讨提高地下空铁换乘空间步行 可达性的策略。本文运用空间句法中的凸状空间法和视域分割法，结合集成度、可见度等形态变 量，对成都双流机场T2航站楼的地下空铁换乘空间的步行可达性进行量化分析，据此得出现 状问题和做出具体的优化设计，并进行结果验证。得出如下结论：合理的节点空间设计可增强 换乘导向性；连通换乘空间形成合理的换乘流线可提高换乘效率；有机整合换乘空间及其周围 空间可丰富换乘体验。该研究可为国内外航站楼地下空铁换乘空间的设计提供参考和借鉴。

Study on Pedestrian Accessibility of Underground Transfer Space Between Air and Rail Based on Empirical Analysis of Space Syntax: The Case of Shuangliu Airport T2 Terminal in Chengdu City

The integrated development of air and railway makes it an inevitable requirement for convenient transfer between the terminal building and the urban railway. The height limit of aviation makes the transfer space between air and rail mostly located underground, the complicated transfer flow caused by multi-line transfers and the weak perception of transfer space caused by underground space lead to low air-to-rail transfer efficiency and poor comfort, the pedestrian accessibility of the transfer space is a key factor affecting transfer efficiency and transfer comfort. Shuangliu Airport T2 Terminal in Chengdu, integrates the transfer between the three transportation modes including airport, high-speed rail and subway. By studying the walking accessibility of the transfer space in this typical case, the strategies to improve the walkability of the underground air-to-rail transfer space were discussed. The pedestrian accessibility of the transfer space is essentially the study of the interrelationship between architectural space and human walking behavior. Space syntax has been widely used in accessibility research, it takes the space ontology as the research object, and uses the graphical model to quantitatively study the characteristics of human walking behavior in the space, which provides a research method that can be used for reference in this research. According to space syntax theory, the convenience and visibility of space were used to study the pedestrian accessibility of underground air-to-rail transfer space in this research. The spatial convenience reflects whether the plane layout of the underground air-to-rail transfer space enables passengers to transfer conveniently. In this study, the convex space method was used to abstract the three-dimensional transfer space into the two-dimensional topological diagram composed of several convex spaces, and the number of topological steps was used to judge the convenience of a certain point. The spatial visibility reflects whether the traffic flow line organization of the underground air-to-rail transfer space can better guide passengers to their destinations. In this study, the horizon segmentation method was used to divide the transfer space into grids, and the visual relationship was used to judge the visibility of a certain point. Through the investigation of the current situation, it was known that the station hall floors of the intercity high-speed railway and Metro Line 10 were all located in the underground of the station square of the T2 terminal of Chengdu Shuangliu Airport, the halls were arranged side by side and connected to the second underground floor of the T2 terminal. The arrival and departure floors of the airport were located on the first and third floors respectively, and were vertically connected to the arrival and departure airport traffic hall on the second underground floor through four vertical traffic cores. The transfer traffic flow between the airport, subway and high-speed rail was mainly in the arrival and departure airport traffic hall, L2 channel, L3 channel, and L4 channel on the second underground floor. The arrival and departure airport traffic hall and L3 channel were important passages for air-to-rail transfers, which were necessary spaces for the transfer between the airport and the subway and high-speed rail. There were three transfer routes between the airport and the subway, which were L2 channel, L3 channel, and L4 channel. There was only one transfer route between the airport and the high-speed rail, that was, L3 channel and its extension, and it must pass through the transfer space between the airport and the subway. Based on the spatial syntax analysis, the following current problems were found: 1) the connection between the arrival and departure airport traffic hall and L2 channel, L3 channel, and L4 channel was the node space for the underground air-to-rail transfer, and its integration needed to be improved. 2) L3 channel was the transfer passage between the airport, the high-speed rail, and the subway, and its visibility needed to be improved. 3) L2 channel and L4 channel were the transfer passages between the airport and the subway, and their integration and visibility needed to be improved. 4) The integration of the high-speed railway station halls needed to be improved. 5) The visibility of the subway station halls needed to be improved. Combining the current problems, the following optimization design strategies were proposed: 1) The width of the entrances and exits of the two self-service ticket offices, which were set up beside the structural pillars on both sides of the junction of the arrival and departure airport traffic hall and L3 channel, was reduced to expand the node space. 2) L2 channel and L4 channel were connected to L3 channel, to increase the transfer passage between the airport and the high-speed rail. 3) Commercial or public service facilities were added on both sides of the arrival and departure airport traffic hall, both sides of the extension of L3 channel, and both sides of the transverse passage connecting L2 channel and L4 channel and the extension of L3 channel. Based on the comparative analysis of the results after gradual optimization, the following conclusions were obtained: 1) reasonable node space design could enhance transfer orientation, 2) connecting the transfer space to form a reasonable transfer line could improve transfer efficiency, 3) integrating the transfer space and its surrounding space could enrich transfer experience. The research can provide reference for the design of underground air-rail transfer space in domestic and international terminals.