| Urban road greening environment involved in the urban traffic,construction,water cons ervancy,and other aspects. Urban road greening constructed urban road landscape system,and also affected the urban road traffic safety. Through the study on the green landscape and traffic safety function of road,it make the urban road greening purify and beautify the environment,at the same time,take more auxiliary road traffic safety responsibility.Firstly,Using the method of literature review and summary,it made theoretical investigation on three aspects including road structure classification, road conditions and traffic participants,and expounded the relationship between road greening and them to lay the foundation for road landscape and safety function research.Secondly,by adopting the combination of special literature research and field research methods,it investigated and analysised road greening landscape and safety function in Nanjing city.Thirdly,aimed at the problems found in the research,this paper discussed the road greening plant growth rule and reasonable spacing planting which under the driving vision induction to provide the reference for the modification of road greening related specification.The main results were as follows:1?In the aspect of road landscape,the results of the survey showed that: road greening landscape in Nanjing is good,and greening patterns are varied,and plant species are rich,but the used repetition rate of part of the hedgeshrubs is higher.In the aspect of road landscape, the results show that the road green belts used 167 plant species,belonging to70 families, 119 genera, including 6 families,11 genera and 13 species of gymnosperms,63 families, 108 genera and 154 species of angiosperms,1 families,1genera and 1species of fern species.According to the road greening degree of beauty, the results of quantitative evaluation of SBE value for evaluation of the road which show that 46 strip of road are disliked; 46 strip of road are liked, and the rate of them is close to 1:1. According to the road plant landscape SBE value of nanjing city, the overall sequencing of six area as follows, Xuanwu district(SBE = 3.405)>Jianye district(SBE = 1.625) > Qixia district(SBE = 1.145)>Qinhuai district(SBE =-0.777)>Yuhuatai(SBE =-3.41)>Gulou district(SBE =-3.547).2?In terms of urban road greening safety function,the results of the survey show that road greening in Nanjing has security assistance functions to the traffic,but at the same time,it has five potential safety hazard which may affect the traffic safety:(1)green shade road signs;(2)The visibility of triangle area controled by the driver safety line of sight distance in no signal control intersection,the traffic line of sight obscured;(3)Road greening plants occupy space transportation;(4)The road by the side at the road crossingwithin the scope of a certain distance grow green plants cause the driver line of sight is not fully;(5)Road greening plant planting design is not reasonable, affect mechanical maintenance and securit.Greening plants invading road space, resulting in safe hidden trouble, the top nine occurrences species are:Ginkgo biloba,Malus halliana,Lagerstroemia indica,Celtis sinensis,Zelkova serrata,Prunus subhirtella,Osmanthus fragrans,Prunus Mume,Acerpalmatum.3?According to the vehicle greenbelt design norms of?urban road greening plan an d design specification(CJJ75-1997)?,it found that Lijiang road,Lushan road, Songshan ro ad,Bancang street, Huangshan road, Taishan road, Shuiximen street, Huanling road, Xinmo fan road and so on,which trees planting design in the road green belts that do not meet the requirements.Through the validation of ?urban road greening plan and design specific ation(CJJ75-1997)?,it found that in the absence of signal control intersection visibility w ithin the scope of the triangle, green belts and roadside greenbelt plants should be keptd riving the line of sight is qualitative description,and it lack of corresponding quantitative standards.According to the size of the green structure of each road kerbstone, green tree planting should be performed according to the actual planting width.It have shown some limitations on Nanjing road greening landscape and its security functions.4?It studied two key problems including road greening plant growth dynamic model and reasonable induction distance.Found that the road greening growth rule are greatly influenced by vehicles and artificial pruning, the scope of its growth is limited within the scope of the width of road green belts.Planting reasonable spacing of the central green plants were confirmed under different design speeds.In the road straight segment structure m odel,under different design speed to form continuous landscape green plants growingin the middle of the reasonable distance L at 20 km/h, is 1.16 m; at 30 km/h, is 1.74 m; a t 40 km/h, is 2.32 m; at 60 km/h, is 3.48 m; at 80 km/h, is 4.64 m; at 100 km/h,is 5.80 m.In the structural model of the curve, its maximum curvature accurate perception accuracy were found,in 40 km/h, 13.30 m; when 50 km/h, 23.37 m; in the 60 km/h, 27.73m;in the 60 km/h, 57.74 m.To keep the curve curvature perceive high accuracy, and maintain the best induction effect, the actual plant spacing must be set up according to space. |
PDF Full Text Request