Studying On Influence Factors And Improvement Measures On Outdoor Thermal And Acoustic Environment Of Urban Residential Area

Since the reform and opening-up policy in 1980 s in China,with constant promotion of society and economy,the urban construction develops rapidly at an unprecedented speed,but urban heat island,environmental noise and other urban problems follow,which greatly reduce life quality of resident,even affect resident health.Taiyuan,Shanxi in central China as research area in this dissertation,using GIS technology,remote sensing technology,field measurement,deep learning simulation analysis,etc.to conduct further and systematic research to influence factors and improvement measures of thermal environment and acoustic environment in urban and residential areas.On the research of thermal environment in urban and residential areas,select Landsat8 remote sensing images of two time phases in summer,combine MODIS remote sensing data at the corresponding period and adopt surface temperature retrieval split window algorithm suitable for Landsat8 thermal infrared band proposed by the author to conduct surface temperature retrieval to the urban area in Taiyuan.On this basis,conduct spatial distribution structural analysis to surface temperature,evaluate and compare urban heat island effect intensity in different areas and time phases,with urban heat island effect intensity index considering spatial aggregation effect proposed by the author.The result shows that,in terms of overall urban area of Taiyuan,though the surface thermal environment high temperature distribution of two time phases without greatly concentrated high temperature aggregation heat island phenomenon,many small high temperature patches occur in urban area of Taiyuan,and for residential areas,the high temperature aggregation phenomenon is more obvious.Extract vegetation cover and impervious surface cover of urban area of Taiyuan in two time phases by Landsat8 multi-spectrum data,and based on this,research correlativity of surface temperature with vegetation cover and impervious surface cover.The calculation result shows that urban surface temperature has significant negative correlation and positive correlation respectively with vegetation coverage and impervious surface coverage.Analyses of the surface thermal environment of two time phases in 8 sample residential areas in Taiyuan show that the thermal environment performance in residential areas is closely related to partial thermal environment and internal surface spatial structure.If adjacent to large-scale concentrated scale green land or water,it can effectively reduce the temperature of residential areas through local cross-ventilation,and in case of low greening rate,high harden ground rate and building density,local heat island phenomenon will occur,which will make high temperature aggregation patches occur within residential areas.Meanwhile,comparison verification is conducted to remote sensing retrieval temperature by field measurement data,and the verification result shows that the retrieval result is basically consistent with actual measured result.In the correlation analysis of residential areas temperature and various residential area indexes,it is found that average temperature in residential areas has obvious negative correlation with greening rate,strong positive correlation with building density,and has little correlation with other residential area indexes and air temperature.In addition,conduct questionnaire survey on environmental comfort level of residential areas,and through analysis of questionnaire,it can be concluded that: The air temperature,solar radiation and green coverage rate are major factors affecting resident subjective thermal feelings;The thermal comfort level of people to thermal environment in residential areas is related to greening rate and green land arrangement form.Therefore,increase of water area and green coverage rate in residential areas will affect air temperature and air humidity within residential areas,adjust microenvironment within residential areas,and further improve thermal environment.The newest artificial intelligence technology—deep learning,GIS and remote sensing technology is also used in this dissertation to conduct improvement measures simulation analysis to Taiyuan central urban area surface thermal environment.Simulation result indicates that: Under the premise of adding total scale of green land,the improvement measure with best effect is the park green land arrangement by combination of large,medium and small sizes;Generally speaking,the circle and square green land patches have the best cooling effect,and the triangle green land patches have the lowest improvement effect and other similar conclusions.There are some suggestions on improvement measures against the thermal environment for urban and residential areas based on analysis of simulation result.For improvement and planning of the thermal environment of main urban area,firstly,build cooling planning system for ?one ring,one axis,double wedges,multi-corridor,and multi-point? multi-layer network on the spatial pattern of land use status in quo and ecological environment in main urban area;Secondly,rational planning,build ecological corridor system in the form of increasing wedge green land with the main urban periphery to link with ecological hinterland of the urban periphery,introducing cool air of urban periphery into the cities;Thirdly,through the scientific and rational planning and implementation of the old city transformation,with small green patch shape dominated,the appropriate increase in green coverage breaks up the heat island patches status in quo,effectively improving the urban thermal environment of the old city;Fourthly,increase park green land in the form of combination of large,medium and small sizes in the main urban area,build cool island for cities,and provide resting and vacation spots while effectively alleviating the thermal island for cities;Fifthly,by changing the geometric shape of the existing green land monosome and the scientific and rational layout of the green land group layout,give full play to the integrated role of green land in alleviating urban thermal island;Sixthly,through the three-dimensional greening,such as roof greening and wall greening,under the premise of not increasing the green land,effectively increase green coverage,and effectively improve the thermal environment and living environment within residential areas.In the study of the acoustic environment of residential areas,according to two kinds of classification methods,we choose the sample of residential areas to test,which contains a total of 12 street residential areas and 48 samples points,and have quantitative study of impact of urban expressway,trunk roads and secondary main roads traffic noise on environmental noise at the side near streets,the side behind streets and residential areas.Through the statistical analysis of measured data,the results show that: Taiyuan traffic noise of expressway and main roads noise level generally exceed the standard,and the noise of the secondary main roads is basically within the limited field specified in the noise specification.Residential environment noise situation is not optimistic,and 71% of the residents in the subjective questionnaire survey are interfered by noise.The correlation analysis of sound source shows that: Traffic noise for expressway is the main noise source for the adjacent residential areas.The noise source of residential areas near the urban main roads and the secondary main roads is relatively complex,and the traffic noise of adjacent roads is not the main noise source.In the frequency sound pressure level,medium and the low-frequency noise of urban expressway causes the highest impact.Therefore,the acoustic environment in the residential areas is affected by adjacent roads traffic noise.Prevention of the traffic noise of urban expressway is the key point,and traffic noise of main roads and secondary roads cannot be neglected.This dissertation analyzes the measures to improve the acoustic environment of residential areas from two aspects of noise sources and transmission channels.Control strategy based on traffic noise sources: Put forward the comprehensive urban traffic planning,and promote "green transport" concept;Control of vehicle and road noise;Utilization of some traffic control measures,etc.The noise reduction strategy via noise transmission: Put forward to control the distance between residential buildings and roads;Effective setting green belt;Insert the noise barrier into the roads and residential areas;Rational planning the elements of residential areas reduces the impact of human activity noise,etc.For the acoustic environment of residential areas of Taiyuan City in current situation,two major categories of branched expressway,trunk roads near the city,residential areas adjacent to the expressway shall mainly use porous asphalt noise-reduction roads,green soil embankment,sunken roads,additional buildings near street,and the simulation of sound field is carried out in four residential areas near expressway by using the Cadna/A simulation method.This dissertation analyzes the acoustic environment in residential areas of the trunk roads near cities,and carries out the noise reduction simulations after adopting corresponding measures in the residential areas.For the particularity of low-frequency noise,and danger of low-frequency traffic noise on the residential areas,put forward the strategy to reduce the impact of low-frequency traffic noise,etc.For the measure of reducing temperature and noise,this dissertation proposes a layout pattern of green lands in residential areas,with its quantity meeting the requirements of greening rate of certain residential areas,in a form of representation,taking a residential area in Taiyuan as an example,the result of the simulation research on the thermal environment and acoustic environment after adding green land shows that the "central green land + surrounding green belt" pattern has been improved in two aspects of the thermo-acoustic environment.With the development of effective use of urban space and promotion of national policy,the opening residential areas building are inevitable.The dissertation discusses change in thermo-acoustic environment of residential areas in the new pattern of the opening residential areas.It is suggested that the urban thermal island intensity will not be increased after the opening of the residential areas,and it may even contribute to the cooling in the summer when certain conditions are met.For the acoustic environment,it is believed that the increase in traffic noise on the roads is bound to have an impact on the households and the surrounding environment,but it is necessary to follow the view of "big opening and small enclosure",use rich and complete commercial buildings near streets,or use proposed new composite external wall "ecological wall" to form enclosure layout for residential area groups,creating quiet space within residential area group.