Drained uplift capacity of deeply embedded horizontal circular plate anchors in sand

Abstract

Plate anchors are an attractive anchoring solution for offshore renewable energy due to their high capacity-to-weight ratio. Estimation of anchor uplift capacity is essential to determine the required embedment depth. However, shortcomings exist in estimating the drained uplift capacity of deeply embedded plate anchors in sand. This paper presents a finite element method (FEM) analysis and a new limit equilibrium method (LEM) solution for determining the drained uplift capacity of deeply embedded horizontal circular plate anchors in sand. The FEM analysis, implementing a modified SANISAND constitutive model, is employed to simulate the behaviour of sand during anchor uplift for different embedment ratios and relative densities. The simulated failure mechanism and mobilised friction angles are subsequently used to develop the LEM solution. Compared to existing LEM solutions, the proposed solution can capture the plateau in anchor capacity with increasing embedment depth, in conjunction with the transition from a shallow to a deep failure mechanism. The key features of the proposed solution include the consideration of soil arching, thus enabling better estimation of deeply embedded anchor uplift capacity.