Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Effect of Willow Tree Root on Slope Stability

Document Type : Original Research Paper

Authors
Mohammad Hadi Davoudi 1
Seyed Mahmoud Fatemi-Aghda 2
Gholamreza Shahalipour 2
1 Soil Conservation & Watershed Management Research Institute, Tehran, Iran
2 Faculty of Sciences, Tarbiat-Moallem University, Tehran, Iran
Abstract
Tree root, as a reinforcing agent, may improve the stability of soil slopes by two mechanisms: a decrease in the developed shear stress via distribution of applied loads within a larger area, an increase in the mobilized shear resistance via its tensile strength. The latter, in addition to mechanical properties of root, is a function of diameter, number, orientation and deflection angle of the roots with respect to the potential slip surface. Coppin & Richard analytical model was used to asses to what extend willow tree roots can improve the stability factor of a planar slip surface. The required data were provided by a series of in-situ tests in Taleghan region using a large scale field shear stress test apparatus. Tests were run in a natural deposit with and without willow root to measure cohesion and internal friction angle of soil under different root density. At the end of the tests, the diameter and angle at which the roots were deviated and cut were measured in the sheared zone. Experimental results were used in the model for different water levels, revealing that for a 45 degree planar slip surface and a root density of 5 to 26 percent the safety factor rises between 0.5 to 36 percent.
Keywords
Root density
Shear zone
Willow tree root
Planar slip surface
Soil slope
Shear resistance

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 15, Issue 59
Spring 2006, Vol. 15, No.59
Spring 2006
Pages 84-93