Study On Optimization Of Downtown Landuse In Tianjin Towards Eco-Security

City is the assemble of mankind modern civilization. Urban planning is a city-science which is to predict a city's future development and is a means to meet the propose of the urban development for the economic, social and ecological space requirements, through land resources allocation in the urban areas constructed or to be constructed. Because the city's living environment is gradual eroded by the crisis of pollution, resource depletion and ecological imbalance, urban planning, together with other disciplines, is trying to restore the health of urban systems. People gradually realized that in order to maintain urban civilization sustainable development, the city must be built based on the protection of ecological security and also realized that making the living space safe is an important basis for the eco-security system. Although the urban land in the central city is a small part of the total city land, but it is the largest intensity, highest intensity and strongest economic and social benefits artificial plaque within the total area, its advantages and disadvantages of the eco-security state will inevitably significant impact on the overall ecological environment.The land-use and land-layout for construction of central city is one of the main tasks of urban planning, it has a decisive role eventually make the eco-security target achieve, through physical carrier material. This thesis is based on the analysis of the relationship between the two factors, explores to build a interoperable bridge between the urban land use optimal allocation and the research about ecological security in the science of land resources, geography, ecology and other areas, combines the quantitative model with the spatial layout, makes the research results of these cross-cutting subjects play a direct role in the actual development of the city constructing activities. We hope that we can improve the urban ecological security effectively by means of the allocation of resources. Within the process of the combination of the multi-disciplinary, we build a methodology and technology framework which is about the urban land ecological security with double balanced of "quantitative and positioning" and utilization development of disaster prevention and mitigation, in order to guide the urban land and space use optimization and layout according to the current state of urban ecological security.This article starts from the introduction of definition of ecological security, research content and the theory and practice development of eco-security at home and abroad, analyses the relationship between urban land use and ecological safety at the epistemological aspect, constructs the urban ecological security objectives and evaluation system at the methodological aspect, and at the technological aspect gives workable advices of the combination of the quantity structure and spatial distribution for urban land-use in central city, with the example of the land use in the city center of Tianjin. At the same time, targeting the human living environment's quality in central city of Tianjin, the thesis proposes the land use eco-security evaluation indicator, indicators'weights, the correlation between the urban land-use and the indicators, etc. We hope that it can benefit the land use adaptive optimization targeting urban ecological security and may have some reference to other cities in the aspect of land use optimization in order to have a better ecological security condition at technology methods, implementation strategies, etc.This thesis is divided into six chapters.Chapter One introduces the thesis topic background, purpose and significance, summarizes the research trends on urban land use and ecological security at home and abroad, gives a clear scope of the study and the research methods, and explains the contents of the study and research framework.Chapter Two focuses on the origins of the urban eco-security concept, definitions, basic theories, practices and the eco-city construction practice, summarizes the eco-safety problems people facing currently in China.Chapter Three regard the urban land use and ecological security both as single objects, discriminates the relationship between urban land use and ecological security from the angle of reaction and interactions between urban land us change and eco-security, describes the relationship of influence and constraint between the two research objects.As an example of Tianjin,Chapter Four discusses the relevant indicators for the eco-security of urban land use and integrates these indicators into a target system which is based on the experience, ideas and measures about the eco-city and sustainable city at home and abroad, and is also based on the analysis of the security condition of the urban land use in central city of Tianjin. And it proposes the technology framework of urban land use ecological security target system.Chapter Five gives the assessment of urban land use for ecological security (land use eco-security evaluation, LUESE) in Tianjin with the relevant research results, and on the basis of the evaluation results, discusses the relevance between the evaluation indicators and urban land use, gives recommendations to the quantitative structure of land use optimization for the current eco- security condition in central city of Tianjin, which is an optimization suggestions of the quantitative balance. Then, using the space syntax, it simulates the influence to the eco-security when the main urban land correlated to the eco-security most have different sites in the spatial layout in the central city, and give the optimization of the qualitative balance. Finally, it gives out the recommendations for definiting land for eco-security, optimizing the development and utilization of disaster prevention and strategies. Based on the land suitability, proposes the overall layout plan of urban land-use in central city of Tianjin——the main eco-security optimization directions of the functional urban land development and utilization.In Chapter Six, we select the Zhong Xin eco-city to have a second application with the research results, verify the evaluation system, and explore the eco-security evaluation and optimization for urban land use on middle-scale.