An analytical method for a slope reinforced with rigid piles

Stability analyses for a slope are mainly performed using limit equilibrium procedures that calculate a safety factor against shear failure. However, for slopes reinforced with rigid piles, failure modes other than shearing can be critical (i.e. the bending failure). Assuming that the rigid piles in a slope fail due to bending, this paper proposes an analytical method incorporating soil arching for the stability analysis of a rigid pile-reinforced slope. To validate the analytical model and perform the stability analysis of a pile-reinforced slope, a three-dimensional numerical simulation technique using the shear strength reduction method is carried out. It shows that the safety factors predicted by the numerical simulation agree well with those of the analytical method, with the differences being less than 16·0%. The safety factor is found to increase with increase in the bending strength of rigid piles; it also increases as the effective cohesion and effective friction angle of foundation soft soils increase. It is also shown that the effective friction angle of soft soils is the most influential factor affecting the safety of a rigid pile-reinforced slope.