城市中心广场地下街出入口空间上下联动设计

随着中国城镇化进程发展，人口密集、土地资源短缺等问题使得最具活力却拥挤的城市中心区亟需扩张。城市中心广场逐渐向下发展，而地下空间早期粗放型开发模式导致城市中心广场上下割裂。出入口空间在其中承担沟通上下的重要作用，且目前仍存在空间使用效率低下、吸引力不足等问题。文章以城市中心广场地下街出入口行为活动为导向，总结不同类型地下街出入口空间的上下联动行为需求及现状问题，从形态组织、文化功能、通行效率、安全可达四个方面提出城市中心广场地下街出入口空间上下联动设计策略。

Entrance-Exit Connected Designfor Underground Streets in City Central Plazas#br#

With the accelerated development of China's urbanization, urban populations have soared. Environmental deterioration and land shortages have become great challenges that modern large cities must face together, especially in downtown areas with limited land resources and the greatest vitality. Due to continuously increasing land demands for urban construction, lands are developed at a high intensity. To increase space in cities, their central plazas have been gradually reduced. Hence, the development of underground spaces attracts more and more attention. Also, the early extensive open mode of underground spaces has led to the vertical separation of the city central plaza, and people might encounter various barriers to entering underground spaces. 　　The city central plaza is the space with the richest activity in downtown areas. Also, entrances and exits of underground streets are indispensable components in the urban public space system. They connect the ground plaza with the underground space and assume the important function of ground-underground activity integration. Based on a field survey, it was found by the author that, among other problems, entrance and exit spaces of underground streets in city central plazas have low space use and are insufficiently attractive. Researchers worldwide have explored entrance and exit spaces from the perspectives of urban space forms, space structures, space landscapes, space planning, and spatial orientation. However, they have disregarded existing studies on urban space that focus on the needs of behavioral activities. 　　In this study, the concept of entrances to and exits from underground streets in city central plazas was summarized simply. Meanwhile, connotations of the "ground-underground connection" were analyzed. It attempted to establish interactions among people, behaviors, and spaces in various contexts by exploring behavioral activities of people and space environmental features. Field surveys were done in entrance spaces of underground streets of two city central plazas in Chongqing and Chengdu, and objective environmental uses of activity groups were quantized from the perspective of behaviors. First, preliminary surveys and interviews were done on the behavioral activities and people in underground street entrance spaces of the plazas. On that basis, characteristics and behavioral types of activity groups, including fast commuting, slow commuting, resting, communication, and interaction, were summarized. Second, behaviors in entrance spaces were observed and recorded regularly. An activity print map was established by field counting and map marking methods. The general situations of spaces and behavioral activities were analyzed by plotting the activity population curve. Also, entrance and exit space types were summarized, including road edge, business expansion, composite center, and railway extension types. Third, behavioral demands and spatial characteristics were analyzed through a stationary point observation method and photographic recording and observation. A space-behavior graph was plotted to analyze entrance and exit spaces of various types, the behavioral needs of groups at entrance and exit spaces, and the spatial characteristics. Finally, the ground-underground connected behavioral needs and status in entrance and exit spaces of various types of underground streets were summarized to explore relevant design elements. The ground-underground connection design strategies in entrance and exit spaces of underground streets in the city central plazas were proposed from the perspective of optimizing morphological organization, introducing cultural functions, improving commuting efficiency, and guaranteeing safe accessibility. Those strategies were to perfect the urban public space system and improve urban space vitality.