Vertical bearing capacity of bucket foundations in sand

• Published in: Ocean engineering Vol. 121; pp. 453 - 461
• Main Authors: Park, Jeong-Seon, Park, Duhee, Yoo, Jin-Kwon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.07.2016
• Subjects: Arching; Bridging; Bucket foundation; Buckets; Foundations; Marine; Mathematical analysis; Mathematical models; Non-associated flow rule; Sand; Shaft resistance; Shape-depth factor; Soil (material); Stresses; Vertical bearing capacity; Bucket foundation; Shape-depth factor; Vertical bearing capacity; Arching; Non-associated flow rule; Shaft resistance
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2016.05.056

Bucket foundations are widely used to support offshore structures. The vertical capacity of bucket foundations in clays has been extensively studied. However, the unique load transfer characteristics of bucket foundations in sands are not well documented. We perform a series of two-dimensional axisymmetric finite element analyses using the Mohr-Coulomb model following a non-associated flow rule. Because the depth-to-diameter ratio of a bucket foundation is much lower compared with that of a pile, a higher level of arching is shown to occur in the soil. A pronounced increase in the horizontal stress and a corresponding increase in the shaft resistance (Qs) are observed. The arching also causes the failure surface to widen due to additional vertical stress imposed on the soil. Based on numerical results, predictive equations for Qs and a combined shape and depth factor for the base capacity (Qb) are proposed for bucket foundations in sands that follow a non-associated flow rule. •We perform axisymmetric finite element analyses to determine the vertical bearing capacity of bucket foundations in sand.•A significant level of arching effect is shown to occur in surrounding soil.•A pronounced increase in shaft resistance is observed because of the arching effect.•Base capacity is shown to be higher than that of an embedded foundation.•Predictive equations for shaft resistance and combined shape-depth factors for base capacity are proposed.