The Effect Of Urban Permeable Pavement System On Local Thermal And Moisture Environment

With the world’s growing population and fast developing economies, the numberand size of city, as the carrier of population and economy, is rising fast in the21stCentury. In this process, the development of urbanization bring the deterioration ofurban thermal climate and a series of problem, such as the significant increase of thesurface temperature, the raise of the disease incidence rate and mortality rate relatedheat city air-temperature, the frequency of extreme weather in summer and increasedthe energy consumption in city. Therefore, the study of city thermal environment is thekey to solve the problem of living environment, energy consumption and personal safety.The urban artificial impermeable pavement system that was mainly used in urbanunderlying surface in the present has a strong relationship with high temperature andUrban Heat Island Phenomenon. Because of its impermeability property, the runoffvolume in city will increase and may cause the flood disaster in the rain. At the sametime, it unable to infiltrate rainwater into the underground, which will damage the citywater balance and destroy the urban ecological environment. In the hot summer itsimpervious makes a dramatic increase in the surface of the underlying surfacetemperature, increase the formation of Urban Heat Island Effect.Due to the pernicious effects of the urban artificial impermeable pavement onurban thermal environment at this stage, a kind of urban underlying surface that canalleviate the intensity of heat island and improve urban thermal environment is urgentlyneeded. The permeable underlying surface has the property of reduce urban surfacerunoff, create a good traffic environment, sound absorption and noise reduction toimprove city acoustic environment and relieve urban heat island intensity. lack of studyabout the urban permeable pavement system improve urban hot and wet climate in thepresent research status of interior and foreign, in this paper, on the basis of experimentalstudy, combine the numerical simulation to study the interaction effect between theurban permeable pavement system and the urban hot and wet climate. Mainly includesthe following sections:1.Through the sample of experiment research methods about the permeability ofpavement system in outdoor, get the data of the temperature and moisture in thepermeable pavement system by taking some sample on the internal and external full testunder the real outdoor weather conditions and analyze the interaction between theporous pavement system and the city local hot and wet climate, in addition, provide thereference data for the next chapter’s numerical simulation.2. Based on the conservation of mass and energy, considering the impact of watertransfer and evaporation on energy balance system, establish the water heat couplingmodel of the permeable pavement system and atmospheric heat and moisture exchange. Finally, based on the coupled water and heat model, programming calculation moduleand compared with the experimental results in the second chapter to verify thecalculation module.3. Take the established water and heat coupling model between permeablepavement system and atmospheric heat and moisture exchange as a sub modules intothe urban regional thermal climate prediction model, and then use the new model tosimulate and analyze the thermal environment of actual planning project in southernbuilding residential area, in the end, obtain the real effect of porous pavement system onthermal environment.The main results and condusions are as follows:1. The sample of experiment research methods shows: under natural rainfallconditions, the moisture content of the permeable paving system in the deep inside therubble layer and soil layer are grow up with the continuous natural rainfall, and thetemperature inside the layers of the system from top to down increase. Under differentartificial rainfall conditions, the greater of the rainfall, the faster of rainwater infiltrationin the system, and the smaller temperature fluctuations between the internal layers ofpermeable paving system after the rain.2. By comparative analysis the results of the numerical simulation andexperimental shows: The model results on the trends and magnitude of temperature andmoisture content are consistent with the actual results, and the model can meet the needsof the research.3. Contrast the numerical simulation of permeable and non-permeable pavementsystems in the actual residential shows: with outdoor air temperature drop, the outdoormoisture content rises, the corresponding underlying surface temperature is reduced,and the comfort and human thermal sensation increase; With the permeable underlyingsurface coverage increases, the outdoor temperature decreases and the moisture contentincreased gradually; Compare the different combinations of underlying surface shows,choose a different function of the underlying surface type to design and adjustment canachieve the purposes of remission urban heat island and improve the urban heat climate.