Experimental Study On Slope Stabilization Effect Of Different Vegetation Allocation Patterns

Vegetation measure is an effective method to control mountain disasters.In this dissertation,in order to explore the slope stabilization effects of different vegetation allocation models under the extreme climatic condition(rainfall intensity 118 mm/h)on slopes of 20°,35°,50° and 60°,the vegetation models were used to replace the real plants,and a total of 32 indoor model slope artificial rainfall experiments were carried out.In the experiment,three slope types with arbor are constructed,including wide-band close planting,narrow-band close planting and equidistant sparse planting;moreover,three shrub slope types are constructed,including densely planted,moderate planted and sparse planted;finally,there is also a herbaceous slope type and a bare slope control group.Based on the model experimental,the failure process and mode of the experimental slope are analyzed,and the correction formulas of four groups of slope safety factors are derived.In addition,this dissertation also evaluates the instability risk of each experimental slope,and constructs a comprehensive slope stability evaluation system,as well as optimizes the vegetation allocation mode of each experimental slope.Thus,we developed a comprehensive treatment technical scheme of vegetation measures for Laohuzui and zhenzhutan landslide disaster in Jiuzhaigou Valley scenic spot.The main findings of this dissertation are as follows:(1)By analyzing the slope failure process in rainfall experiments,four different slope failure modes are summarized in this dissertation.They are(1)Progressive destruction,which mainly appears on bare slopes and herbaceous slopes;(2)Segmented destruction,it mainly appears on the 50° and 60° extremely steep slopes of trees;(3)Gully erosion,it mainly appears on the slopes of trees and shrubs at 20°and 35°;(4)Overall sliding damage,it only appears on the shrub slope moderately planted at 60°.(2)Different vegetation types contain different slope stabilization mechanisms and slope thresholds.The slope stabilization threshold of arbors and shrubs was about35° ? 50°,meanwhile arbors and shrubs planted on 20° ? 35° slopes had better reinforcement effect.In this slope range of 20° ? 35°,the optimal arbor planting pattern is wide band close planting,and the optimal shrub planting pattern is densely planted.However,planting trees and shrubs on steep slopes above 50° will increase the risk of slope instability,and the more densely planted,the worse the slope safety.Furthermore,herbaceous plant can delay the time of slope failure and reduce the risk of slope failure between 20° and 60°.But,with the increase of Slope Gradient,the effect of herbaceous plant on slope protection decreases gradually.(3)By comparing the slope reinforcement effects of 8 different vegetation allocation patterns on the same slope,it is found that the optimal vegetation allocation mode of different slope is different.On the steep slope of about 20 °,the plant type and planting density can be selected flexibly.On a steep slope of about 35 °,the optimal vegetation configuration mode is the wide-band dense planting arbor.On the extremely steep slope of about 50 °,the wide-band dense planting arbor is the comparatively superior vegetation disposition pattern,but it should be used together with other engineering reinforcement measures.On the extremely steep slope of about60 °,this dissertation does not recommend the use of vegetation measures to control landslide disasters.