Numerical Investigation Into the Keying Process of a Plate Anchor Vertically Installed in Cohesionless Soil

Abstract

Vertically driven plate anchors offer an attractive anchoring solution for floating offshore structures, as they are both highly efficient and suitable for a wide range of soil conditions. Since they are oriented vertically after installation, keying is required to orient the anchor into the direction of applied loading. Simulation of the keying process has not been extensively investigated by previous research, especially for cohesionless soil. Reliable prediction of irrecoverable embedment loss during keying is needed, since such loss can lead to significant reduction in the uplift capacity of the plate anchors. Large deformation finite element analyses LDFE method using RITSS (Remeshing and Interpolation Technique with Small Strain) were used to simulate the keying process of strip plate anchor embedded in uniform cohesionless soil. LDFE showed that the loss in embedment depth of plate anchor during rotation is inversely proportional to the loading eccentricity e/B. It was also found that the maximum pullout capacity occurs before the end of keying process at orientations between 60° to 85° degrees for vertical loading. Also, the LDFE study showed that reduced elastic soil stiffness leading to increased levels of displacement at which the peak load is approached.