Study On Engineering Properties Of Root Soil And Its Application In Ecological Slope Stability Analysis

Ecological slope protection has some hydrology effects, such as rainfall interception,inhibition of surface runoff, enhance soil permeability. And the effect mechanical reinforcementof plant root system can improve the intensity. Both combined action give play to slopeprotection. Today, people pay close attention to environmental protection and life quality. At thesame time, ecological slope protection has other advantages such as engineering protection,maintaining ecological landscape, which has become the preferred solution used for slopeprotection of highway. This paper bases on ecological protection project from Longnan Liren toYang Cun during Daqing-Guangzhou highway. From the view of the mechanical andhydrological effect of ecological slope protection, to research the impacts of roots influenced byreinforcement, permeability and interception performance, both which influence slope stability.The main contents and conclusions are summarized as follows:(1) Based on the effect mechanical reinforcement of plant root system, the soil shearstrength influenced by moisture content, root weight and root distribution were studied throughdirect shearing tests. The results reveraled that root-soil composite still complies with Coulombtheory, the addition of plant root system could significantly increase shear strength of soil, andthe shear strength increased with root weight increased. However, the shear strength of root-soilcomposite decreased with moisture content increased. The contribution for soil shear strengthwas enhanced by different root distribution.(2) On the basis of hydrological effect for ecological slope protection, the permeability ofsoil influenced by root weight and root distribution was studied through falling headpermeability tests. The results showed that plant roots could increase the porosity of soil,improve permeability of soil and the permeability coefficient increases with the increase of rootbiomass. The permeability coefficient exihibited the maximum when root weight reached0.25%.Whereafter the permeability coefficient decreases with the increase of root biomass. Thecontribution for permeability was enhanced by different root distribution. Herbaceous plantintercept2.95mm rainfall equally, which is equivalent to15.8%of rainfall interception rate.(3) Taking the influence of the root system on reinforcement, permeability change andinterception into account simultaneously, to analysis the influence of herbaceous vegetation onthe slope stability under the condition of rainfall with the method of numerical analysis, whichtake granite soil slope of Longnan Liren to Yang Cun during Daqing-Guangzhou highway asexample. The results indicated that the safety factor of vegetation slope is bigger than bare slope.And the positive effect by improving of shear strength and interception is overtop the negativeeffect by increasing permeability. It is efficient for promoting slope stability...