Performance assessment of laterally loaded piles in slopes subjected to cyclic loading

The reduction in lateral load capacity and the progressive loss of stiffness in piles on sloping ground are primarily caused by cyclic loads. This study evaluates the response of rigid and flexible piles embedded in dry sand on a 1V:3H slope versus horizontal ground. A series of 1-g model tests was conducted to investigate the effects of forward and reverse loading, loading frequency, and the cyclic loading pattern (one-way and two-way) on secant stiffness, cumulative displacement, and bending moments. Results indicate that under reverse loading conditions, the secant stiffness increases with the number of cycles and attains higher values. However, this trend is reversed when considering the hysteresis loop area. These findings highlight the significant influence of the cyclic loading pattern on soil–pile interaction, with two-way cyclic loading signifying a pronounced improvement in both soil stiffness and lateral load resistance compared to other loading conditions.