Quantitative Study On Rainwater、Stagnation Function Of Green Roof

At present,due to the factors such as rapid urbanization and changes in land use forms,the impervious surface area of cities has increased greatly,which has changed the runoff pattern of rainwater,and the municipal rainwater pipes have been subjected to excessive pressure,leading to severe flooding in the city.As the proportion of population increases,land use in China is also very tight.The traditional form of drainage and waterproofing can no longer better optimize the urban drainage problem.As a more direct means of regulation and control in the construction of sponge cities,the green roof,emphasizing that the six-character policy of “Infiltration,stagnation,storage,net,utilization and drainage”in the process of natural rainfall can regulate and control the urban runoff from the source and solve the serious waterlogging problem in the city at present,therefore,it is urgent to study the parameters that affect the green roof’s hysteresis and flow capacity.This study first analyzes and determines the parameters that affect the green roof hysteresis and flow capacity,and then quantitatively studies the relationship among the parameters through experimental means,the experimental contents are as follows: the short-time heavy rainfall experiment is carried out on the simple green roof with the same structural layer,the duration of each experiment is fixed,the duration of rainfall is kept consistent,and the intensity of rainfall is adjusted in each experiment,the general law of rainfall runoff of simple green roof is induced by observing the variation of seepage runoff of structural layer of green roof Finally,the mathematical research method is used to establish the relationship between the change of seepage yield and rainfall intensity under the green roof and the relationship model between the delay time of flood peak and rainfall intensity,with a view to follow-up in the practical application to play a guiding role in the average annual rainfall intensity reasonable design of green roof paving area.The final results show that the green roof has a certain hysteresis and flow capacity for natural rainfall,and its hysteresis and retention capacity are closely related to the intensity of rainfall.