Effect of soil moisture content on the deformation behaviour of root-reinforced soils subjected to shear

This paper presents an experimental study on how soil moisture content affects the deformation behaviour within root-reinforced soils subjected to shear. In-situ shear tests were carried out in this research. The plant used in the shear tests was Prickly Sesban (Sesbania cannabina Merr.). The shear deformation within the root-reinforced soil after shear was measured. The effect of soil moisture content and the root area ratio on the development of the shear zone was investigated. The experimental results showed that the deformed shape within the soil for root-reinforced soils subjected to shear correlated well with the exponential decay function. The width of the shear zone of root-reinforced soils increases with increasing soil moisture content. Additionally, the width of the shear zone increases with increasing root area ratio. Widths of the shear zone developed in front of and beside the root structure are greater than those behind the root structure. Finally, the mechanism between the shear strength increase provided by roots and the development of the shear zone width are discussed in this paper.