Analysis On The Functional Pattern And Co-evolution Trend Of The “Three Lives” In The Beijing-Tianjin-Hebei Urban Circle

In order to realize the synergetic development of Beijing-Tianjin-Hebei region,this paper quantitatively measures the niche-fitness of "Production-Living-Ecological" functional of the Beijing-Tianjin-Hebei region and analyzes the spatial-temporal differentiation characteristics the niche-fitness of "Production-Living-Ecological" functional.In addition,we identify the type of urban circle in the Beijing-Tianjin-Hebei region,and reveal the functional pattern and coordinated evolution of the "Production-Living-Ecological" function in the urban circle of Beijing-Tianjin-Hebei region.Firstly,based on the niche-fitness evaluation index system of "Production-Living-Ecological" function,we measure the niche-fitness of the "Production-Living-Ecological" function in the Beijing-Tianjin-Hebei region in 2011 and 2016.The results show that,from the time,the niche-fitness of production function and ecological function remain basically unchanged,and the niche-fitness of living function is on the rise;from the perspective of space,the niche-fitness of "Production-Living-Ecological" function of Beijing-Tianjin-Hebei has obvious spatial heterogeneity.The niche-fitness of production function is high in the central region and low in the northwest region;and the niche-fitness of life function obeys the central-peripheral model.But the distribution of ecological functions is just opposite to the production function.Secondly,based on the evaluation of the niche-fitness of the "Production-Living-Ecological" function in the Beijing-Tianjin-Hebei region,the cohesive subgroup analysis was carried out on the Beijing-Tianjin-Hebei region by means of the gravity model and social network analysis method.The study found that the urban units in the Beijing-Tianjin-Hebei region have broken the limit of administrative boundaries and formed urban groups across regions.Thirdly,combining gravity,cohesive subgroups,and network centrality,this paper identifies production-type urban circles,living-type urban circles,eco-type urban circles and Comprehensive urban circles in the Beijing-Tianjin-Hebei region,and analyzes the coordinated evolution trend of various urban circles.The results show that the number of production-type urban circle and life-type urban circle has increased,showing a trend of gathering in Beijing and Tianjin.The number of eco-type urban circles is basically unchanged,and distributed in an "axial shape",forming a continuous ecological link.Finally,according to the development status of the urban circle,the paper puts forward the optimization countermeasures of "Production-Living-Ecological" function pattern: Taking the urban circle as the carrier medium of the local urban system,The government should formulate the relevant policies to strengthen the virtuous circle of economic development,social life,and ecological environment among urban units,promote the integration of "Production-Living-Ecological",and finally realize the synergetic development of Beijing-Tianjin-Hebei.