Influence of Plant Roots On Slope Stabilization: A Geotechnical Investigation
Abstract Direct shear tests conducted on soil samples reveal that soils with plant roots show an increase in cohesive factor but increase in frictional angle is insignificant. Displacement and shear strength graphs, however, indicate that soil with plant roots can withstand more shear stresses. Among the three plant species selected for the present study, Chimonobambusa sp. has the highest shear strength increment, ∆C = 5.0 KN/m2 followed by Cymbopogon sp., and Pseudosasa japonica with 4.5KN/m2 and 1.0KN/m2 shear strength increments respectively. An increase in shear strength is also observed in the reinforced soils with increase in number of roots of these plant species. Cymbopogon sp. has higher root density near the surface but decreases with increasing depth and absent at 320mm depth, Pseudosasa japonica has the lowest root density but penetrates deeper up to 530mm while Chimonobambusa sp. penetrates deepest at 700mm with lateral branches extending up to 650mm. Cymbopogon sp., and Pseudosasa japonica may be useful as a bioengineering tool to mitigate soil erosion while Chimonobambusa sp. to mitigate both erosion and shallow landslides.