The Research For Space Distribution Of Greenbelt Network In The "Open Block" Context

The concept of“open block”and sponge city has been a hot issue in the urban planning of the times,in relation to which the green network city theory puts forward a new solution that making use of the existing outdoor space in order to form the strongly connected green network.The concept and key point of urban greenbelt network has been raised.By analyzing the space construction of block,attached outdoor space is considered to be the main spatial carrier.As the main targets of“open block”are gated communities and danwei unit,by analyzing the spatial features and practical problems of which,the result shows that the isolated outdoor space is difficult to satisfy the needs of the residents.Connect the critical outdoor space identified to reshape the outdoor space.On account of the importance of attached greenbelt and low elevation greenbelt in sponge city,the low elevation surface of the attached greenbelt is considered to be the key point of sponge block construction.This paper chooses DEM to simulating the overland flow path of the block.By simulating three typical distinctive blocks(mountainous,river-net and plain),three features(parallel tree topology,unsystematic tree topology and hybrid tree topology)are summarized.According to the relative planimetric position between overland flow path and outdoor space,three categories(overlapping,separated and disjoint)are summarized,and following which there are three spatial fitting patterns(autochthonous fitting,malposed fitting and allopatric fitting).As a method of urban greenbelt network layout,key space information extracting,spatial fitting and Spatial overlay is put forward,as well as the point line and area space structure.Wuhan,a typical plain city,is chosen as the site background.Optical valley area(1.14km~2)is an empirical application for the low elevation greenbelt network.The key hydrogeology spatial information is extracted on the basis of DEM,and the key spatial information of residents outdoor activities is extracted by means of field observation and questionnaire survey.The framework of low elevation greenbelt network spatial morphology is formed by fitting the above two key spatial information.Based on the total annual runoff control of Wuhan and its corresponding design rainfall,using water volume in facility size related calculation formula,calculate the target area of total annual runoff control in low elevation greenbelt network,thus the minimal area of green lands and water is obtained.The finally space allocation plan is based on the framework of the spatial morphology and specify areas.