Research On The Evolution And Influencing Mechanism Of Urban Spatial Form In Dangtu County

Since reform and opening-up and under the background of globalization,rapid industrialization and urbanization have promoted the rapid expansion of the city's scale,and the urban space pattern has continued to "expand" and "grow higher".While the external form of the city is expanding,the urban form has become more multidimensional and complex,resulting in the lack of urban spatial features and the low quality of living environment.In the new era of urban and rural development,how the factors of urban spatial growth change,how these factors act on the existing urban space,and how to shape a sustainable habitat environment in the new era,are the basic tasks facing urban and rural planning and design.At the same time,in China's urban and rural planning system,urban construction and the research of small cities have been very weak in China,and there is relatively little research on the influencing mechanism in the development of small cities.The request of urban and rural integration and rural revitalization indicates that the development of small cities will become one of the important strategies in the future of our country.Therefore,facing the requirements of the transformation and promotion of small cities in the new era,this paper takes Dangtu County as an example to study the evolving characteristics of its spatial form and the influencing mechanism,in order to lead a healthy development of the central city of Dangtu County.And provide reference for the study of space growth for other small cities.Dangtu County is located in the economic circle of the Yangtze River Delta,the bridgehead that develops eastward in Anhui Province has historically been the gateway to the ancient capital Jinling(now Nanjing).It is now the county under the jurisdiction of Maanshan City(a member city of Nanjing Metropolitan Area).The county covers a area of 1,002 square kilometers with a total population of480,000 people,jurisdiction over 10 towns and 1 township.In 2017,it ranked the 72 nd among the top 100 counties in China.The thesis is composed of five parts.The first part is introduction,expounding the background and purpose of the research,determining the research objects and contents,combing the related research at home and abroad,and determining the research methods and technical routes based on the literature review.The second part summarizes the historical development and spatial evolution of the cities in Dangtu County from ancient times,modern times,after the founding of the People's Republic of China and since the reform and opening-up.Dividing the development of the county after the founding of the People's Republic of China into four stages: 1949-1977,1978-2001,2002-2011,and 2012-2017.Each stage has different spatial features.Finally,the structure of "double core,two axes,six zones,and two groups" was formed.The third part analyzes the spatial expansion and morphological changes of the built-up area of Dangtu County.The periodic variation characteristics of external expansion are analyzed by means of the method of expansion strength,pattern and structure.The changes of internal structure are analyzed from the aspects of the composition productive,living,and public service land,spatial height distribution,etc.The method of "three-center aggregation" was introduced to analyze the changes of geometric center of the county,population center,transportation center,and the change of "center of gravity triangle".The evolution of the center is the projection of the evolution of spatial morphology.The fourth part comprehensively analyzes the evolution of urban space patterns in Dangtu County from the following six aspects: nature and resources,history and humanities,society and economy,facilities and transportation,policies and planning,regions and divisions.Spatial development is the result of multiple factors acting together and overlapping.After the founding of the country,Dangtu County's dominant factors in the four stages are different.The dominant role played is also changingalternately,which is reflected in the spatial coupling between the urban functional structure and the "center of gravity triangle." The fifth part summarizes the research results and main conclusions of the paper,pointing out the shortcomings and the direction and path of subsequent research.