The Reconstruction Scheme For The Built Residential District Of Northern Jiangsu Based On The Sponge City Concept

In terms of the basic concept of sponge city,it is to build an ecological drainage system,make full use of urban roads,greenbelt and drainage system to fully absorb rainwater,as well as give play to the capacity of "stagnation","infiltration","storage" and "purification" of low impact rainwater development facilities,so as to make the urban construction have the function of natural accumulation,natural infiltration and natural purification.As an important part of the city,the residential district accounts for 40% of the urban land,while its rainwater runoff accounts for 50% of the total urban runoff.Therefore,it is very vital to use the concept of sponge city to effectively control the rainwater runoff of the built residential district and realize the coordinated development of human settlements,environment and ecology.In this paper,it takes the built residential district in Northern Jiangsu Province as the research object.In view of the existing problems of the built residential district to determine the influencing factors of sponge city construction,which then formulates the sponge renovation scheme of the built residential district in Northern Jiangsu Province.And the conclusions obtained are as follows:(1)On the basis of summarizing the theory of sponge city construction and the research on practical case at home and abroad,it obtains the research method of sponge renovation of the built residential district.According to the analysis of the building type,underlying surface composition,drainage system and other problems of the built residential district,it formulates the design principle and process guided by the problems.Through the combination of the current situation of the residential district,it uses a low impact construction mode to effectively deal with the problems faced by the built residential district.Besides,it selects the sponge facilities such as permeable pavement,grass planting ditch,rainwater garden and so on for reasonable configuration,so as to construct the drainage system of rainwater infiltration,transmission and storage,which can play the role of green facilities in reducing rainwater runoff.Finally,it checks the sponge construction target in line with the annual total runoff control rate and runoff pollution control rate,so as to verify the feasibility of the study.(2)It explores the influencing factors of sponge city construction,which puts forward more targeted renovation strategies according to the differences of influencing factors.Firstly,it obtains the applicability of sponge city construction from the characteristics of regional location climate and precipitation.Since the location factors are related to the sponge construction goals,the parameter assignment of the value of each construction goal is also affected by it.Secondly,the geological conditions are closely related to the implementation and effect of sponge construction.Based on the analysis of several elements of geological conditions,it obtains a LID(Low Impacet Development)facility suitable for different soil conditions.Moreover,it analyzes the specific influencing factors of the construction site,which mainly includes the site vertical planning,network of drains,construction conditions and so on,so as to reasonably divide the catchment area,organically connect all relevant parts of the site,and form the overall system.Since sponge city construction is a complex project,it is necessary to consider all the influencing factors as a whole to realize the rationality and effectiveness.(3)From the analysis of research methods and influencing factors,it takes a residential district built in Northern Jiangsu as an example,which puts forward the specific design strategy of sponge renovation.What’s more,it determines the design method and technical route,divide the catchment area by the site vertical planning and current network of drains,formulates the layout and scale of LID facilities by the construction conditions and calculation methods of LID facilities,draws and designs the construction map,as well as achieves the design goal of local sponge city construction through calculation,verification and adjustment,so as to prove the feasibility of the study.Finally,it estimates the construction cost of the reconstruction project,carries out the relevant economic benefit analysis,and puts forward the corresponding countermeasures for the problems existing in the sponge construction at present.Through the research in this paper,it comprehensively introduces the methods and strategies of sponge renovation of the built residential districts in Northern Jiangsu,which provides the design reference for the sponge construction of the residential districts in Northern Jiangsu.On the other hand,it puts forward the influencing factors of sponge construction,which provides design ideas to help the sponge city construction.Through the combination of the design of construction drawings,it fills the lack of construction drawing design experience in the current field.In the research process,it obtains the method of layout scale of LID facilities as well as the calculation method and parameter ratio of each facility layout in the check method,which are of certain reference value to the design and check method in this field.