Analysis Of Root-Soil Interaction And Shallow Stability Of Vegetated Slope

At present, the study on mechanism of vegetated slope still lags behind the application of vegetated slope. The mechanical effect for vegetated slope can be available from the estimate of tensile strength of the root, but this method don't give consideration to the action of deform and strength of the root in slope movement, so it is necessary for us to research the interaction between root and soil for vegetated slope and to use it in the shallow stability analysis.Through data collection and analysis both in china and abroad, the paper set forth influencing factors for slope protection with vegetation, such as root distribution in the slope, type of instability for slope, distribution density of the root and root strength, etc, also set forth some vegetation which will be applied to slope protection and mechanism of interaction between root and soil. Then through the generalization of interaction model between herbaceous plant root and soil, the paper put forward some improvements on depth of shear zone for Waldron interaction model between root and soil and the action length of root in shearing condition which has been approved by testing data. For interaction model between woody-plant root with large diameter and soil, lateral loaded-pile model with small displacement and flexible-cable rope model with large displacement will prevail.By the way of analysis on shallow stability of vegetated slope to which the aforesaid improved interaction model between herbaceous plant root and soil has been applied, it was concluded that shallow stability will go down with increasing slope angle, increasing depth and width of slope sliding part, and increasing length-width ratio of slope sliding part. Slope with protection will be more stable than the one without slope protection, and it will be more stable with smaller root diameter, increasing area ratio between root and soil, increasing angle between roots and shear plane. At last, through the analysis of shallow stability for slope protected with woody plant, the result is that slope stability will go down with increasing distance between trees and increasing breast-height diameter.