Soil-Root Interaction and Effects on Slope Stability Analysis


N. Ali1, I. Farshchi1, M.A. Mu’azu2* and S.W. Rees3

1 Faculty of Civil Engineering, Universiti Teknologi, Malaysia, 81310 UTM Skudai
2 UTM Razak School of Engineering and Advanced Technology, UTM International Campus, 54100 Kuala Lumpur, Malaysia
3 Cardiff School of Engineering, Queen’s Buildings, CF24 3AA, Cardiff
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This work combines the mechanical and hydrological effects of vegetation with a slope stability framework. The analysis provides further understanding of the effects of vegetation on slope stability analysis. From the results obtained, trees contribute to the stability of sloping ground both hydrologically as a result of increase in matric suction of the soil resulting in a increase in the shear strength while mechanically is due to root reinforcement, the shear strength of the rooted soil mass is enhanced due to the presence of a root matrix. It is found that the most significant benefit is likely to be achieved only when the tree is located at the toe of the slope. The results indicate that the Factor of Safety against failure can increase by more than 8% when including the influence of a mature tree located at toe of a slope. The results also indicate that the mechanical contribution to strength offered by vegetation is much greater than the influence of hydrological effects.
KEYWORDS: Roots, Soil, Suction, Slope stability, Trees, Vegetation.

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