Thrust and bending moment of rigid piles subjected to moving soil

An experimental apparatus was developed to investigate the behaviour of vertically loaded free-head piles in sand undergoing lateral soil movement (w_f). A large number of tests have been conducted to date. Presented here are 14 typical model pile tests concerning two diameters, two vertical pile loading levels, and varying sliding depths with the movement w_f driven by a triangular loading block. Results are provided for driving force as well as for induced shear force (T), bending moment (M), and deflection (y) along the piles with w_f/normalized sliding depth. The tests enable simple expressions to be proposed, drawn from the theory for a laterally loaded pile. The new expressions well capture the evolution of M, T, and y with soil movement observed in current model tests, and the three to five times difference in maximum bending moment (M_max) from the two modes of loading. They further offer a good estimate of M_max for eight in situ pile tests and one centrifuge test pile. The study quantifies the sliding resistance offered by a pile for the given w_f profiles, pile location (relative to the boundary), and vertical load. It establishes the linear correlation between the maximum thrust (resistance T) and M_max, regardless of the magnitudes of w_f.