The Vegetation Protection For Highway’s Side Slope

Since the construction of the national highway boosts progress, the areas of side slops increase along. Which may cause such ecological environment issues as less earth natural coverage, soil erosion, soil weathering, which can lead to instability of the slopes, bring hidden dangers and decrease their service life, however slope vegetation effectively solve these ecological problems. The vegetation and the soil on slopes are interdependent and mutually promotive, first, the vegetation is not only provide the habitat of the living beings, but also provide their feeder directly or indirectly; on the other hand, slope vegetation determines the up growth of the soil to a large extend, while animals play significant role in the formation of the vegetation and its distribution. Neither of them can exist solely or independently. Last, The ecological effect of vegetation is that they can be indicate the environment enhancement function and landscape function as well. And assist to increase the driving safety, and comfort by ameliorating the highway landscape.In the research, we select a common F. Arundiance, L. perenne and C. dactylon as the test objects, respectively, the following test and get the appropriate conclusions: (1) In root tensile strength test, the results show that the stretching resistance of the roots and the diameters are directly proportional to each other, while the tensile strength is indirectly to. With the same root’s diameter, the tensile strengths of L. perenne and F.arundiance are higher than that of C. dactylon; as a result we can argue that the anchoring effect from the Cynodonteae is the worst. When we design the vegetation covered slopes, we can use more L. perenne and F. arundiance while the C. dactylon can be decreased.(2) Seeding experiments, the monoseeding and mixed spawning experiments for the L. perenne, F. arundiance and C. dactylon on their emergence of seedlings, cover degree, underground biomass, and soil disintegration have indicated that the nixed spawning seeds are in good compatibility, while the soil reinforcement and the corrosion resistance are much more stable than the single seeding.(3) Rainfall test. We found that in the wash-out tests on the3mixed spawning combinations, when the rainfall is relatively light, the soil erosions from the combinations are similar, but when the rainfall gets heavier, the erosion gets more correspondingly, the difference among3combinations are more noticeable. At the same time, the NP erosion is proportional to the rainfall too, and from macroscopic view the trend is similar to that of the soil erosion. Under the light rainfall, the quick-acting of NP and the soil are eroded together, while the heavy rainfall, the NP erosion is taken place with the sediment mostly, which leads to the sudden increase of the NP erosion on the surface of the slopes. When the rainfall reaches one level, the NP erosions of3combinations are getting closer, which can be caused by the limitation of the vegetation functions on the slopes. It means that when the rainfall is beyond the critical point, the function gets weakened, and the soil erosion tends to the maximum. (4)We found that The combination (F. arundiance lOg/m2+L. perenne20g/m2+C. dactylon20g/m2) has the best records, which means it exerts the best impact on the decrease of the soil erosion on slopes. The results can be applicable to the slope protection project, which can be helpful for the designs of the Synthesis Protection for the highway’s slopes.