Horizontal behavior and failure mechanism of group suction piles under monotonic loading varying with pile spacing

Abstract

A suction pile has been regarded as an effective offshore foundation owing to its simple construction and removal. In this study, a group suction pile (i.e., a group format of a single-suction pile) was proposed to enhance the insufficient horizontal resistance given by a single suction pile. The effect of pile spacing on the horizontal resistance of the group suction pile under monotonic horizontal loading was evaluated. Group suction piles in a 3 × 3 arrangement were prepared with different pile spacings (2D, 3D, and 4D) and a large-scale soil chamber was used. The horizontal behavior of the group suction pile was analyzed by varying the loading positions. The effect of suction on the horizontal load response of the group suction pile was discussed. Particle image velocimetry (PIV) analysis was used to track the movement of the group suction pile in terms of horizontal movement, vertical movement, and rotation. The PIV analysis classified the failure modes of the group suction pile as forward overturning, backward overturning, and sliding. The results revealed that the rotational tendency during horizontal load testing governed the horizontal resistance of the group suction pile.