Study On The Expressway's Road Greening

The expressway construction made a great harmful impact to ecological environment. In order to eliminate the demolishment, the expressway greening hadbeen an important part of the expressway construction.The expressway greening is mainly composed of three parts: road greening, service station greening and interchange district greening. Among them, road greening is the emphasis of this paper, including the following three aspects: middle departing belt greening, side slope greening and laterally pretectal belt greening. The main content is as follows.1. The analysis of micro-climate site of the road greenbeltIn the building process of expressway, a lot of calcareousness, powder of coal ash, asphaltum and stone were put into used. On one hand, it completely destroys the original soil structure, making the soil really barren, on the other hand, the rise of roadbed also affects the ground water to go up, making the soil very drought. Besides, the fast and busy cars flux, the complicated variable landforms make the highway extremely hot in summer, cold and windy in winter, and the atmosphere is seriously polluted. All these factors go against the growth of plants.2. The selection of plants in the road greeningRoad greening has its own special soil conditions. It is very crucial to select the plants to achieve the success of the road greening. "Adjust measures to local conditions, suitable plants and suitable road, simple planting, easy management" are the principle of plants selection. There are different plants growing in various climates and geographic conditions. According to the four main districts in Jiangsu province, this paper analyzes the natural conditions in each district, and lists its indigenous plants and the external fine species which are suitable for the road greening.3. The plant arrangement mode of the road greeningEach part of the road greening has different functions and technological requirements. Middle departing belt is responsible for preventing the dizzy from the opposite vehicles;side slope greening is responsible for fixing the soil and protecting the slope; laterally pretectal belt greening is responsible for improving the road environment such as preventing the noise and dust. Under this precondition, this paper put forward various viewing mode by selecting diverse plants and arranging plants scientifically and reasonably.4. The maintenance management of the road greeningMaintenance management is one of the key factors for the success of the road greening. Expressway's distance is long, area is large. So the maintenancemanagement is loaded with trivial details and difficulties. This paper is based on the author's investigation and practice experience, analyzing the necessity of each maintenance management busywork and putting forward the specific implement methods.5. Case analysisThis paper has analyzed three cases in sum, there are:(l)The slope greening in Lianxu expressway's Pizhou part: emphasis on analyzing the situation of plants growing in the side slope greening and comparing.(2)The greening in NingHang expressway's Jiangsu part: because the main point of NingHang expressway is landscape design, the main task is to conclude the plants arrangement in the middle departing belt and the means of side slope and laterally pretectal belt greening.(3)Nanjing airport expressway's road greening: as a highway which has been opened to traffic for six years, it's successful experience is worth to study and use for reference. So this paper puts emphasis on analyzing the plants selection and arrangement means.6. Benefit of greening analysis.Road greening not only produces nice social and environmental benefit, such as improving driving environment and exerting ecological functions, but also gains nice economic benefit, such as saving the cost and lowering the operating expenses.