In bridge engineering, the decision to extend raking piles of an abutment under an embankment requires careful consideration. The complex interaction between the ground, the angled pile group, and the embankment’s settlement makes movement prediction challenging.
If raking piles are placed beneath an embankment, the settlement of the soil behind the abutment can induce significant bending moments in the piles. This phenomenon, as highlighted by Dr. Edmund C Hambly in 1979, poses a risk of pile damage. The angled orientation of raking piles makes them more susceptible to bending stresses compared to vertical piles, as the settlement-induced forces act at an angle, amplifying the bending moment.
Therefore, while raking piles offer valuable support in resisting lateral forces, extending them under an embankment may not always be advisable. The potential for excessive bending moments and subsequent pile damage necessitates a thorough geotechnical investigation and careful engineering analysis to assess the feasibility and risks involved.