Research On Green Roof Design Of Fengxi New City Based On Sponge City Theory

China’s total water resources are scarce,and the regional and seasonal distribution of rainwater is uneven.Due to the destruction of the natural environment by urbanization and the increase in the level of hardening of the ground,China has brought serious ecological problems such as the deterioration of the water ecological environment and the urban heat island effect.Based on this environmental background,China drew on foreign advanced stormwater management experience and put forward the sponge city theory based on China’s national conditions,and launched the first batch of sponge city construction nationwide in 2014.Sponge city construction needs to combine various low-impact development measures.The research object of this article is the green roof,which is an important measure to reduce the source of roof rainwater in low-impact development measures.China is still in the stage of practice and exploration of sponge city construction.At present,there are few researches on the design of green roofs under the sponge city theory.Xi Xian New Area,as the first batch of new sponge city pilot areas in China,is specifically aimed at Fengxi New City.Research on green roofs in the Northwest is even scarce.Therefore,this paper investigates and studies the green roof construction under the sponge city theory of Fengxi New City at this stage,summarizes its construction status and existing problems,and discusses the design method and promotion strategy of green roof under the sponge city theory in Northwest China.It then promoted the construction of green roofs under the theory of China’s sponge city.First of all,this article expounds the development context of sponge cities and green roofs and the current research status of related theories at home and abroad,and summarizes the research hotspots and research frontiers of the two in each period.Secondly,it defines the related concepts and research scope of sponge city and green roof,and clarifies the relationship between the two and the contribution and benefits that green roof construction can bring to sponge city.Thirdly,this paper investigates and studies the current roof status of Fengxi New City and classifies existing roof types,and selects eight representative green roof construction projects in the first batch of sponge city pilot areas in Fengxi New City for systematic research.Summarize its operating status,design methods,structural characteristics,rainwater flow and benefits to the sponge city,and analyze and summarize the results of green roof construction under the existing sponge city theory of Fengxi New City,as well as the effectiveness,management and diversity of the three Aspects of existing problems.Subsequently,the analysis puts forward a design strategy suitable for the promotion and construction of green roofs under the theory of sponge cities in the northwest region represented by Fengxi New City.It is proposed to guide policies and regulations at the national level.At the design level,green planting can be considered in the early stage of the design,and rich building shapes can be used to increase the number and area of three-dimensional space "sponges".The regional vegetation adopted by Fengxi New City is summarized,and the principle of selecting green roof vegetation is proposed.This paper summarized the research on the adaptation mode of the green roof of Fengxi New City,and explored the adaptation mode of the green roof of Fengxi New City from the three aspects of roof environmental elements,roof type characteristics,and greening mode requirements.The structural design of green roofs is classified into five categories:container green roofs,sloped green roofs,simple green roofs,garden green roofs and blue-green roofs.Finally,according to the matching of the green roof and the existing roof types of Fengxi New City,the ecological and economic benefits that can be brought about by the comprehensive construction of a green roof in the whole area of Fengxi New City,the urban core built-up area and the sponge city pilot area are calculated.