改革开放后中国城镇化进程长期保持较高速度发展，天津作为东部沿海重要的特大城市，影响城市发展和空间结构变化的动力机制较为复杂。基于天津遥感影像解译建设用地、常住人口分布等基础数据，本论文对空间结构演变进行全过程记录，在表象特征客观归纳基础上，并与城市发展动力机制理论框架相比较，进行空间结构演化系统分析。既有助于解释天津城市演化的动力机制和发展趋势，也有助于通过天津案例对有关理论的适用性进行判断。本论文研究结论可归纳为三方面：一是在天津城市空间结构的演变现象方面，主要特征包括：天津经历了改革开放初期的双中心扩张、中心城区集聚扩张、轴带扩张、点状增长等四个城市空间结构演变阶段。1980年代和2002至2013年是天津城市空间结构演变的重要时期。前一时期奠定了天津“一市双城”的基本空间结构，后一个时期呈现出大尺度蔓延的特征，是扩张最为剧烈的时期。二是对产生上述现象的原因，分析认为其动力机制如下。1、天津地方政府通过城市总体规划进行的有意引导发挥了较大作用，按照规划在园区发展、土地供应、交通建设等方面进行强力引导，城市总体规划和重点地区规划的实施使城市空间结构不断演变，体现出政府推动力的主导作用。2、城市空间结构的演变在一定程度上反映了市场力。市场力在市域尺度上难以影响城市总体空间结构，但在企业选址、园区建设的中等尺度上，市场主体发挥一定促进作用。对于不符合市场需求的政府规划，市场体现出较强的制约作用。3、社会力长期无显著作用，近年来在微观尺度上略有体现。主要表现在由于公民意识的发展，对城市个别具体建设项目有微弱影响，但不足以影响城市空间结构。社会力量在空间选择上受到政府与市场所形成的政商联盟的强力制约。三是通过对天津实践的分析，对基于西方城市政体理论的“三元动力机制模型”进行了适用性研究和理论框架修正，提出围绕政府力和市场力的“二元动力机制模型”：政府、市场是推动城市空间结构演化的主要动力，政府主导作用突出；社会处于政府的管治之下，并非一种独立的作用力量；兼具政府和市场双重特征的国有企业是一种混合型动力主体，起到了重要作用。未来应对这一模型进行调整和优化，以保持制度框架的稳定和城市发展的可持续。除以上研究结论外，本论文建立的空间数据库可用于天津市域的持续性研究。
Since the reform and opening up, China's urbanization process is in the stage of accelerating development. As an important megacity in the east coast of China, the evolution process and dynamic mechanism of Tianjin's urban spatial structure are complex in this process.Based on the basic data such as remote sensing construction land and resident population distribution, this paper conducts a systematic analysis of the process of spatial structure evolution. The comparison between the phenomenon of Tianjin’s urban spatial structure change and the theory of dynamic mechanism of urban development will not only help to explain the dynamic mechanism and development trend of Tianjin's urban evolution, but also help to judge the applicability of the theory objectively.The research conclusions can be summarized into the following three aspects:Firstly, there are two characteristics in the evolutional phenomenon of Tianjin urban spatial structure. 1) The urban spatial structure of Tianjin has experienced four stages of evolution: the dual-center expansion in the early stage of reform and opening up, the central city area agglomeration, the one-axis-one-belt expansion and the overall regional growth. The main increment has been concentrated on the main axis of the Haihe River of “Wuqing--Central city area--Core area of Binhai New Area. 2) The 1980s and 2000s are two important periods for the evolution of urban spatial structure in Tianjin. The former period laid the basic spatial structure of "one city and two cores" in Tianjin. In the latter period, Tianjin's urban expansion is the most rapid and structural evolution is the most drastic, showing the characteristics of large-scale land spread, which will have a significant impact on the urban inventory space optimization.Secondly, this paper believes that the dynamic mechanism of the above phenomena has the following reasons.1. Tianjin’s urban spatial structure is closely related to urban master plan. According to the master plan, the government has played a significant role in the economic parks development, the residential land supply, the construction of transportation facilities and other aspects. The implementation of the urban master plan and the key areas plans has made the urban spatial structure constantly evolve, reflecting the driving force of the local government and leading the change of Tianjin’s urban spatial structure.2. The evolution of urban spatial structure reflects the power of market to some extent. It is difficult for market power to influence the overall development direction of the city on the scale of the whole city, but enterprises as the main body of the market play a strong role in the medium scale urban construction activities such as economic park development. In addition, for government plans that do not meet real needs, the market can play a strong restraining role.3. Social forces outside the government and the market have not played a significant role for a long time, but have been slightly reflected on the micro scale in recent years. Due to the development of civic awareness, social forces can play games with the government and the market on the type and site selection of individual construction projects, but they are not enough to affect the urban spatial structure of Tianjin. Citizens are strongly restricted by political and business alliances in their choice of living space.Thirdly, through the analysis of the practice in Tianjin, this paper revises the "Thernary Dynamic Mechanism Model" based on the Urban Regime Theory(URT), and puts forward the "Dual Dynamic Mechanism Model " centered on government force and market force: Government and market are the main driving forces to promote the evolution of urban spatial structure, and the government's leading role is prominent; The society is under the administration of the government and is not an independent force; The state-owned enterprises (SOEs), which have the characteristics of both government and market, are a special kind of driving force, which play an important role in the evolution of urban spatial structure and move between government and market. This phenomenon should be optimized in the future to maintain the stability of the institutional framework and the sustainability of urban development.In addition to the above research conclusions, this study established an object-relational geographic database covering the administrative boundary, constructional area, population, park boundary and other data, which can be used for continuous researches.
