Of Highway Slope Plant Protection Technology Research

This paper, taking the vegetable protection technology of slope of the highway in loess area as study object, through the techniques of site investigation, experiment and entity project testing and verifying, focuses on the systematic study of vegetable protection technology used in loess highway, protecting-slope plants, protecting effects and selection of protecting schemes and puts forward a series of vegetable protecting schemes of slope in loess highway, which are relatively reasonable. The achievements are as follows:Through large-scale site investigation, eight geological structure modes of slope in loess highway are concluded, among which the amount of slopes that consist of Q₃ new loess and Q₂ old loess are the most, taking above 42% of the total. The deformation modes of high slope in loess highway are mainly slope-surface-erosion and area feature peeling; collapse, slumping and slide could only be seen in some parts of the road section. Peeling mainly happens in the slope surface where fossil soil bares; erosional fossa and dropping hole are mostly seen on the slope consisted of new loess, but few on the slope of old loess. Erosion mostly happens from the edge of plat, and then extends to the inner gradually. Vegetable protection is very effectively to prevent the loess slope from erosion.Technical mechanism of vegetable protection is analyzed, the technology of vegetable protection in loess slope and construction technics are studied systematically. It is believed that the effects of three vegetable protection techniques are good, which are planting trees on plat, grass- planting spraying in thick layer base material and grass- planting spraying with three-dimension vegetative net. When designing slope protection in loess highway, these techniques could be adopted according to the actual conditions.Rainfall simulation experiment on site shows that runoff from the top of slope is the main destroying reason for slope surface. Runoff and mud content have peak values in the process of rainfall. Washing and destroying mode of fossil soil which is easier to be destroyed is different from that of loess; it is good to adopt vegetables to protect slopes. The key point of vegetable protection of loess slope is to choose the species which are suitable for the local soil characteristic and water content as far as possible, design mixed-sowing mode by imitating local wild group raise the vegetable surviving ratio by enhancing the later period conservation and defer the protecting-slope vegetable to degenerate. For the fossil soil slope, it is suitable to adopt the grass-panting spraying technology in thick layer base material.