Effect Evaluation Of Slope Protection For Herbs Based On The Grey Connection And Principal Component Analysis

A Slope protection is an important factor for highways construction. The anti-washout ability is good if using traditional slope protection methods, but the ecological and landscape effect are bad. Using vegetation for slope protection can protect slope and make the slope stability, and overcome the shortcoming of traditional slope protection ways. It can fully exert landscape and environment effects of vegetation, and it also has the factor of lower construction cost,better controlling effect and longer work time .People pay more attention to sustainable development nowadays, using vegetation for slope protection becomes a kind of trend in slope protection of highway, it also represent the developing direction of slope protection. But now research result of the technology has lagged behind the practical engineering results because of the mechanism of interaction effect between vegetation root and soil is lack of comprehension, and it have not made a systematical and profound study of selection of vegetation.This paper based on the study of vegetation protection theory and relevant material, it summarizes function mechanism and coverage of effect on mechanics effect and hydrology effect of utilizing plant to protect the slope. Results indicate that the vegetation protection technology strengthen the slope effectively,maintain slope stability and have a key role in ecological landscape.Using grass to protect the slope becomes to be the most basic way of vegetation protection because of its advantage. This article takes Northeast Forestry University tree farm as an experimental field, and select 6 different common herbs in Heilongjiang Province(Trifolium pretense Linn, Agrostis stolonifera Linn., Trrifolium repens L, Bromus inermis Leyss., Lolium perenne L., Elymus trachycaulum) to plant, adopting the method of on -the -spot test to combined with indoor experiment(including the drawing test of roll,the test of slope soil shearing strength on different water content and so on),several important indexes that influence plant protection performance is tested, including the ecology adaptability,slope protection effects and mechanics effects of root, then using grey connection analysis and principal component analysis to appraise slope protection effect of each kind of plant. Results indicate that grass roots have a good capacity of anti-pull-out; the existence of the root system can significantly increase the soil shearing strength and its parameter-cohesion force and internal frictional angle, and weaken the effect of increase of soil water content on slope stability, improve the slope stability factor, it has a good capacity of soil protection and ecological effects of landscape.Different type of grass has different slope protection effect. Experiment show that Lolium perenne L., Bromus inermis Leyss. and Elymus trachycaulum are first choice of vegetation in this conditions, and Lolium perenne L. is best in all factors; then we choose Trrifolium repens L and Trifolium pretense Linn as slope protection plant; the slope protection effect of Agrostis stolonifera Linn. is the worst one of all grass, the slope protection effect has been restricted by undeveloped root system, so its appearance quality and mechanical properties is poor.