Urban Land Expansion Characteristics and Its Forces under Different Stages of Economic Development:A Case Study of Taicang City
以太仓市为例，分析了1989-2008年不同经济发展阶段城市土地扩张的时空特征，发现固定资产投资和二三产业发展是主要驱动力，但不同阶段主导因素不同。
Taking Taicang city as a case,we used expansion speed,expansion intensity index,urban land gravity,methods of grey correlation and binary logistic regression to analyze characteristics,area forces and spatial forces of urban land expansion in different periods from 1989 to 2008 respectively.Results showed that urban land expansion intensity varied with time,and urban land expansion speeded up.The moving direction of urban land gravity changed to north-northeast during the third period form east-northeast during the period of 1989 to 2001.The fixed assets investment,development of the second and tertiary industry,proportion change of the second and tertiary industry,increase of the second and tertiary industry labors were the main forces of urban land area expansion.But the dominant factors were the fixed assets investment and development of the second and tertiary industry during the second time period,and in the third time period,development of the second and tertiary industry,and increase of labors of the second and tertiary industry became the dominant factors.However,other factors such as farmland scarcity index and the per unit area yield of grain had little influence on urban land expansion.The study also showed that all the potential spatial forces had influence on the urban land spatial expansion except for distances to main rivers.However,the factor combinations,the dominant factors and the factors’effects were significantly different in different economic development stages.In order to make urban land expand reasonably,those forces and their mechanism of urban land expansion in different economic development stages should be understood dynamically and systematically from the perspective of area expansion and spatial expansion.