Experimental Study On Slope Reinforcement By Plant Roots

Mechanism of slope reinforcement by plant roots is an important subject that studied comprehensive control of soil-water loss and strengthen prevention of slope geological hazards.Paper relies on the detailed investigation and research project of geological hazards in the Yiluo River Basin and selection a Bermuda grass slope.Comprehensive use of data collection,field in-situ testing,indoor geotechnical tests,theoretical analysis,numerical simulation and other methods.The mechanism of slope reinforcement by plant roots was studied from the following aspects: roots morphology,roots characteristic parameters,roots mechanics reinforcement,hydraulic characteristics of root-soil and strength of root-soil.The main results were achieved as follows:(1)The morphological distribution of roots was obtained,regular expression between roots characteristic parameters were obtained.The roots density,root length density,root volume,roots cross-sectional area ratio and root surface area index decreased exponentially along the depth of soil layer.The root surface area index increases linearly with increase of roots cross-sectional area ratio.(2)The expression between roots characteristic parameters and soil matrix suction of slope was summarized by using markovian pipe double ring infiltration test and indoor soil-water characteristic curve test.Influence depth of roots on soil matrix suction of slope was studied.A functional model suitable for hydraulic characteristics of root-soil was proposed.(3)The expression between roots cross section area ratio and shear strength index was established which based on direct shear test of undisturbed and remolded root-soil samples.The effect of water content and roots tilt angle on shear strength index of root-soil was summarized.(4)Mechanical model of root-soil was derived based on experimental results.Analytical solution of pore water pressure and depth of wetting front of Bermuda grass slope under different rain intensity were deduced based on hydraulic characteristic function model of root-soil,theoretical equation of root water absorption.The calculation model of slope reinforcement by plant roots was established in three working conditions which relative position of combined with potential slip surface depth and root distribution depth of slope,influence depth of roots on soil matrix suction and wetting front depth.