Deformation Characteristics of Bucket−Soil Interaction in Sand during Jacked Penetration

Grouped buckets are an important type of foundation for offshore structures. Because of interactions between buckets, jacked penetration above a group of two buckets is a complicated process that involves complex bucket-soil interactions. In this study, non-contact digital image correlation was applied to study the deformation of sandy soil during jacked penetration. Bucket-group efficiency is negatively correlated with sand density and bucket diameter, and the incremental filling ratio is negatively correlated with sand density and positively correlated with bucket diameter. The graph of the incremental filling ratio versus penetration depth curves is a polyline for a bucket diameter of 5 cm and a hyperbola for 7.5 cm. Buckets in groups experience superposition of their deformation fields, which leads to a partial loss of shear strength. Sand density, bucket diameter, and bucket spacing markedly influence the deformation field of a bucket group, consistent with the force-displacement curves. The bucket-group effect retards the formation of a soil plug.