Zhang+Huawei　Sun+Naidong

Abstract： In the modern city development， PM2.5， heat， air pollution and other ecological problems continue to impact on the city， people begin to think about the city greening how to better improve the city's ecological environment， how to disaster prevention and mitigation in a certain extent. There are two ways to solve these "urban diseases"， one is to cut down the expenditure， and the other is to reduce the pollution source. The two is to open source， increase the amount of green， and improve the ecological self purification ability of the city. However， in the land of the city in the city， the per capita green area occupied less and less. How to solve the shortage of green space？ In this paper， the roof， walls and other buildings on the basis of the three-dimensional greening is undoubtedly an effective way to resolve this contradiction.

Keywords： Sponge city； roof greening； stereo greening

With the continuous improvement of urban land utilization， the use of green space has become very limited， especially in the downtown area of commercial and trade areas， available for less green area. Through the survey found that the benefits of a lot of roof greening. First， it is conducive to carbon sequestration and low-carbon city construction. According to a study by the United Nations Environment deployment， if a city's roof greening rate of more than 70%， the city's carbon dioxide content will drop by 80%. It is widely acknowledged that plants and water are the best ways to adsorb and degrade PM2.5. When the total amount of urban greening to achieve 70% of urban construction， the amount of carbon dioxide over the city will be reduced by 80%， summer temperatures will drop 5-10 degrees Celsius， urban heat island effect will be basically eliminated." Green to the building， will be the only way for the construction of contemporary cities， but also can effectively solve the problem of serious PM2.5， urban waterlogging and other issues.

1 Problems in City of Springs

1.1 We are actually living in the haze of the ghost

Fog and haze， the good environment of the bad spoilers， now more and more frequently involved in our lives. In particular， some of the higher economic level of the metropolis， such as Beijing and Tianjin area， we have been accustomed to haze. This annoying haze， not only caused a lot of traffic tragedy， but also great harm to our body. People suck haze， not immediately have a physical reaction， all kinds of cancer， can not prove that the results of the haze. Moreover， the haze problem is to promote the individual， is scattered， do not form aggregation of social forces， even if the haze is really reduced people's life， it should be after a few years to see the outcome.endprint

1.2 Urban waterlogging caused by heavy rainfall in Ji'nan， 18

July 18， 2007， Ji'nan suffered heavy rain， 3 hours maximum rainfall of 180 mm. Sudden heavy rain caused heavy water in low-lying areas of Ji'nan， parts of the affected areas， most of the road traffic paralysis， causing serious damage to property.

1.3 Urban heat island effect aggravate

The city of speed， the heat capacity of city buildings， dense asphalt and cement pavement has a larger absorption rate and smaller than the outskirts of soil and vegetation， the city area and the surrounding temperature increases rapidly， and the atmosphere in a large amount of radiation， causing the same time urban air temperature is generally higher than the surrounding suburbs temperature.

2 Stereo greening mode

2.1 Building metope greening

Application of Parthenocissus， P.Tricuspidata， Ficus pumila， Xiao Ling， Trachelospermum jasminoides with sucker or aerial roots of vine climbing along the walls， walls， fences， do not need any support and traction materials， the height of up to five or six storeys above the green. Application of grape， wisteria， honeysuckle has wound performance and rambler roses， woody vine length vine， in slightly traction support， climbing in the garden flower， simple scaffolding and perpendicular to the wall bracket and a certain distance， decorating small garden and courtyard etc..

2.2 roof greening

The construction of Roof garden is also a variety of ways， such as using bonsai and reasonable arrangement， form the basin landscape ornamental garden， combined with the situation of the ground， set a fixed planting altar and the arbor， planting flowers and trees， climbing plants and comprehensive bedding planting soil， planting trees， flowers and grass， small garden， garden ground reference layout， construction of the pool stack， rocks， fountain， Tinglang flower， sculptures and other decorative techniques， and open up the path， placing tables， for people in the roof garden viewing， communication and recreation. Do plant density， color， seasonal variation， so good to hear or see， linger.

2.3 Balcony greening

Balcony and windowsill is the floor of the semi outdoor space. In the balcony， windowsill planting vines， flowers and bonsai display， not only make the high-rise building facade with green embellishment， and like the green screen and the vase decorated the doors and windows， add to the living environment and aesthetic feeling of anger.endprint

3 The necessity of developing green space in City of Springs

3.1 Three dimensional greening can effectively reduce the building's energy demand

The three-dimensional green winter warm summer heat， reduce the roof under temperature fluctuation range so as to prolong the life of the roof， has an important role in reducing the energy consumption of air conditioning room on the top floor， it has become a new direction for the development of building energy saving， attracted the attention of many researchers at home and abroad.

3.2 Three dimensional greening is an effective way to enhance the reputation of springs

As a form of urban landscape， three-dimensional greening plays an important role in enhancing the aesthetic sense of urban space. It can maximize the elimination of visual pollution， purifying space， ease the buildings and natural opposites， reproduction of the French poet Paul Aliya described the "built by reinforced concrete in this city， brow feel cool breeze blowing in the jungle" mood.

3.3 Three dimensional greening can effectively alleviate the heat island effect

Most of the construction of the roof of the city is not insulated panels， not only look at the mess， but not heat insulation， summer heat island effect is very obvious. These idle roof if used for greening， the effect will be considerable， resulting in great economic， ecological and social benefits.

4 Conclusions

Ji'nan， a famous historical and cultural city in China， has a long history and beautiful scenery. However， we have to admit that with the development of urban construction and the expansion of the scale of the city， the environmental problems in Ji'nan are becoming more and more serious. The three-dimensional green is not occupied land resources， but also increase the city greening area， improve air quality， beautify the city landscape， at the same time to relieve urban heat island effect， winter warm summer heat insulation and reduce the roof under temperature fluctuation range so as to prolong the life of the roof， has an important role to reduce the energy consumption of air conditioning room on the top floor， it has become a new direction for the development of building energy saving， cause the researchers at home and abroad pay attention to. Therefore， it is necessary to vigorously promote three-dimensional greening in Ji'nan.

Reference：

[1] Wang Qing. Roof garden design and appropriate technology [D]. Chongqing University， 2007

[2] Huang Liang. - fifth facade and roof greening city rainwater utilization [J]. Zhejiang building， 2007 （S1）： 37-39.

[3] anonymous. Two ministries to implement the construction of key projects [J]. sponge city wall materials innovation and building energy saving， 2017 （1）： 9-9.

[4] Zhang Huawei，Li Zhuangzhuang. Modular roof greening device of [J]. China charm， 2016， （45）： 142.endprint