Expressway Slope Ecological Restoration And Landscape Reconstruction

Slope protection, greening and beautifying are important parts of highway construction. Based on Xuzhou-Lianyungang and Nanjing-Hangzhou Expressways and synchronized with the road construction, using the combined means and methods of field test, establishment of pilot demonstration models, position observation and field investigation, and in view of the function of roadbed and cut slope protection, this paper uses ecological protection instead of the traditional engineering protection to control bare soil and rocky slopes.The results from this study show that 1, the protection of highway roadbed slopes should base on the soil condition and use combined forms of vegetation protection and engineering protection instead of entire engineering protection. Critical height of vegetation protection are as follows: 9.5m in clay-soil sector with centralized drainage, and 6.5m in sandy-soil sector with centralized drainage. Both are much bigger than the empirical value 3.0m. 2, As for planting composition patterns of slopes generally mixed planting is better than the simple planting. Especially, the pattern of shrub-grass pattern which links closely together the short-term and long-term protection and landscape functions; and the protection will be long and stable. Seasonal and hierarchial variations break the rigid form of a simple planting and make slope greening both scientific and artistic. 3, As for cut-slope protection, the cement is used as the bonding material in spraying media. Proper proportion of cement has little effect on the germination rate of grass. With the increase of cement content, the germination rate of the grass significantly decreased and seedling growth was affected, except Trifolium repens L., the tested grasses like Festuca arundiacea, Lolium Perenne and Cynodon dactylon (L.) Pers, grew well in media with small proportion of cement, and can almost form lawns. The critical value of cement content is 10%, the growth of all the grasses was inhibited in the media with more than 10% of cement. (4) As for the plant compositions in the spraying, the 7 compositions possessed a certain role in preventing soil erosion. However, possessed different plant compositions had different effect on soil erosion in each month in one year and the concentrated rainfall season. Therefore, attention should be paid to the selection and optimization of plant species. Mixed-sowing of warm-season and cool-season grasses with proper amount of shrub seeds contributed to not only improving the overall effectiveness, but also the phytocoenose's succession in the direction of the one in which shrubs were the dominant species, so as to achieve the combination of both short-term and long-term effects. (5) The comparison, among the 9 types of slope ecological protection in application showed that they had advantages and disadvantages. However, the order of, ordinary spraying＞spraying linked network＞grass bag technology＞grass rod technology＞bamboo dibbling＞grass planting for slope stabilization＞vine slope＞plant strip＞tires for soil fixation (the "＞" means better than). This research solved some practical problems of slope protection in highway construction, and provided a scientific basis for ecological slope protection. So it has a certain theoretical and practical value.