城市空间扩展的自组织特征与规划管控效应评估--以北京市为例

Self-organization characteristics of urban extension and the planning effect evaluation:A case study of Beijing

城市空间自组织是一种潜在的城市发展机制。当前中国正处于快速城市化进程中,正确认识和发挥自组织机制,有效复合空间规划的管控效应,将对城市空间良性扩展至关重要。通过构建空间逻辑斯蒂模型,阐释了城市空间扩展的基本机制,定量诠释了城市空间扩展在"面状"空间规划与"点线状"交通基础设施规划引导下呈现出连续性和复杂性并存的自组织特征。"面状"空间规划体现在区位择优发展、临近建成区拓展等规律,"点线状"交通基础设施规划主要表现为城市空间扩展的不完全预知性。在此基础上,采用相同模型对研究区全域、城市规划建设区、非城市规划建设区进行对比研究,进一步揭示了"面状"空间规划对城市空间扩展的强制性管控作用和"点线状"交通基础设施规划的空间引导作用。因此,为了有效预防规划失效并引导城市空间的良性增长,应当科学使用、谨慎布局"面状"空间规划,需要构建一套顾及城市空间自组织机制,以自下而上的"点线状"交通基础设施规划为基础,并充分发挥好自上而下的"面状"空间规划强制管制功能与"点线面"相协调的综合管控方案。

Self- organization of urban spatial structure is an underlying mechanism of urban development. The correct understanding of self- organizing mechanism and effective compounding of the spatial planning effect is crucial to reasonable urban expansion, especially in the rapid process of urbanization in current China. This paper illustrates the basic mechanism of urban spatial expansion by establishing the logistic model, then quantitatively interprets the characteristics of continuity and complexity which are guided by the ＂planar＂ spatial planning and ＂linear＂ traffic infrastructure planning. The former is characterized by the laws of regional preferential development and adjacent built- up area expansion, and the latter is presented as a pattern of unexpected urban spatial expansion. Based on this assumption, the same model is applied in the whole study area, urban planning construction area and non- urban planning construction area respectively, which further reveals the mandatory control function on urban spatial extension by ＂planar＂ spatial planning and the guiding role of ＂point- like＂ and ＂linear＂ traffic construction planning. Therefore, the ＂planar＂ spatial planning should be analyzed scientifically, in order to effectively prevent planning failure and guide the resonable urban growth. What’s more, the self- organization mechanism of urban space should be established,and the comprehensive control scheme would be put forward based on bottom- up traffic infrastructure planning and top-down ＂planar＂ spatial planning.