Research On Location Influence Mechanism Of Urban Construction Land Expansion In The Yangtze River Delta

The Yangtze River Delta is one of the regions with the highest level of economic development and urbanization in China.It is also the most intense typical area for the expansion of the construction land.The accelerated expansion of urban construction land causes many social,environmental and ecological problems.In addition,the planning urban area is too large and,consequentially,some of construction land is idle.Moreover,the utilization efficiency is lower used.The problem of unreasonable layout of new construction land is relatively low.The location factor plays an important role in the expansion of regional urban construction land use,which is the internal driving force to determine whether the construction land is expanded or not.Against this background,it is necessary to explore the relationship between the expansion of the urban construction land and the different location and the influence mechanism in the Yangtze River Delta.The paper takes the urban construction land in the Yangtze River Delta as its object of inquiry.Through the research of the expansion characteristics and the location influence mechanism of the urban construction land in the Yangtze River Delta from1990 to 2015,this study aims to identify the rules of expansion of the urban construction land and the location mechanism of the urban construction land in the Yangtze River Delta.Besides,this study will attempt to provide a theoretical basis for the rational distribution of new construction land in other coastal areas,including the efficient and sustainable development planning of the economic Park and the reclamation area.The foci of this paper are as follows:(1)A systematic analysis is conducted of the overall characteristics of urban construction land expansion in the Yangtze River Delta,and it is found that the expansion of construction land presents a "W" trend.On that basis,from the three dimensions of expansion stage,expansion space and extension quality,the specific characteristics of the new construction land in the regional cities are described.The expansion of urban construction land in the Yangtze River Delta has a stage characteristic,which is mainly reflected in the quantity and quality of the expansion of the construction land.In the spatial distribution,the Yangtze River Delta region is unevenly distributed.The two sides of the Yangtze River Basin and the adjacent areas of the Hangzhou Bay are the hot areas of the expansion of the construction land of the Yangtze River Delta.The overall expansion intensity of the Yangtze River Delta region is characterized by "diminishing South of Jiangsu and Shanghai regions to the north and south sides,and the decline of Zhejiang coast to the inland region".The regional expansion coordination is generally low,the urbanization is relatively intensive,and the high coordination degree area is mainly in the northern,southern and Yangtze River estuary areas.At the same time,in conjunction with the overall expansion characteristics,the social and economic driving factors of urban construction land expansion in the Yangtze River Delta region are analyzed.The results show that a positive correlation between the industrial structure advanced index,the total population,the per capita disposable income of urban residents,the investment of fixed assets and the area of urban construction land.There is a significant negative correlation between the per capita GDP,the amount of foreign direct investment,the total retail sales of social consumer goods and the area of urban construction land.(2)Through the comparison and analysis of the results of the traditional logistic model and the logistic model based on the internal space factors,the internal driving mechanism of the construction land expansion in the Yangtze River Delta is analyzed.The results show that the stable local factors such as elevation,urban grade,distance from town,traffic line and facilities are the main driving factors for the expansion of the construction land in the Yangtze River Delta.The driving factors of urban location correlation are the determinants of the expansion of the construction land,and the distance between the traffic trunk lines and the facilities has a driving and guiding effect on the expansion direction of the construction land.The elevation factors have certain constraints on the distribution of the new construction land,and the internal space factors have great impact on the new construction land,making the regional spatial connection closer,and the scale effect of urban construction land expansion is more obvious.(3)The microcosmic influence of the main railway lines in the Yangtze River Delta on the changes of the new construction land in the adjacent area is examined with the GIS spatial analysis and the landscape pattern index method.The results show that fact.As the axis of regional development,railway line is an strong booster of regional urban development and construction.It has an important radiation effect on the scale and distribution of surrounding construction land.The newly added construction land in the region has obvious characteristics of railway traffic agglomeration and distance attenuation.(4)With reference to the built-up area above the city scale,an analysis is made of its impact on the expansion and change of the construction land in the adjacent areas.The results show that the urban built-up area,as an important node of regional development,has the influence on the scale and distribution of the new construction land:the closer the distance,the higher the expansion degree,the closer the distribution.In addition,regarding the spatial and temporal characteristics of the expansion of the construction land adjacent to the built-up areas,the higher the urban hierarchy is,the higher the degree of expansion.The city is an important location for the growth of new construction land.Throughout the present study,the urban expansion underwent two stages of development:the urbanization stage based on the inner centripetal filling agglomeration and the suburbanization stage based on the diffusion of the centrifugal marginal layer.It is found that the urban hierarchy and development stage determine the spatial expansion patterns and structural differences of new construction land.