Experimental study on the engineering characteristics of include-straight double-row piles at the edge of the embankment

Abstract

When using pile composite foundation reinforcement for embankments in soft foundation sections, the embankment is prone to differential settlement, sliding, and even collapse. Based on the failure characteristics of pile composite foundation, this article proposes a reinforcement scheme using 'inclined-straight double-row piles' at the toe of the embankment slope. Through model tests, the deformation process, bending moment, and horizontal displacement of the pile body under lateral loading were compared for multiple sets of 'inclined-straight double-row piles'. Combined with numerical simulation analysis, the load-deformation characteristics and failure modes of the inclined-straight double-row piles under lateral loading were revealed, and a calculation analysis model was proposed to provide reference for the practical engineering application. The following conclusions were mainly drawn: (1) Under lateral loading, the inclined-straight double-row piles experience horizontal displacement, followed by bending deformation, with the inner piles failing first and the outer piles failing later, showing correlation. The failure load of the double straight piles falls between the inner and outer piles of the inclined-straight double-row piles. Increasing the bending stiffness of the inner piles and the inclination of the outer piles will significantly improve the overall stability. (2) When subjected to lateral loading, the inclined-straight double-row piles may experience overturning failure due to excessive lateral movement of the pile body or fracture failure due to excessive load on the pile body. (3) Calculation analysis models were developed for the overturning failure mode and pile body fracture failure mode.