A Study of Effects of Pile Depth and Stiffness on a Homogeneous Soil Slope Stabilized with Pile

Abstract

A homogeneous soil slope stabilized with one row of pile placed at the middle of slope was analyzed using the limit equilibrium method and the finite element strength reduction method. The effects of the pile depth, strength and stiffness were examined. It was found that the factor of safety (FS) for the slope increases following the increasing pile depth when the pile depth is larger than the depth of the critical slip surface of the same un-piled slope. The critical slip surface could pass through pile body with pile of smaller strength or pass the pile tip with pile of sufficiently large strength. Increase in bending stiffness of the pile can increases the FS but to a certain limit; the pile stiffness needs to be larger than a threshold value to achieve higher FS for the slope. With the increase in FS, both the slope and pile displacements appears to become larger. For piled slopes with the same or similar FS, stiffer pile results in smaller slope and pile displacements, even through the piles can have very similar bending moment and shear force profiles.