Experimental and theoretical investigations on fin configuration effects of dynamically installed anchors in clay

Abstract

Dynamically installed anchor (DIA) for deepwater mooring is an innovative and cost-effective technology in offshore foundation engineering; however, research on the effects of fin configuration of DIAs is limited. This study therefore systematically examines the effects of fin length–width ratio, fin surface area, fin position, and fin shape on the embedment depth and time-dependent holding capacity of DIAs by experimental and theoretical approaches. First, a series of centrifuge tests was performed on four DIA models with an identical fin surface area, but different fin configurations. It is found that the DIA model with short-wide-rectangular fins that are installed at the rear of the shaft achieves deeper embedment depth and higher holding capacity; whereas, the rectangular- and elliptical-shaped DIA models are similar in terms of embedment and capacity. This motivates the proposal for another nine types of finned DIAs in a more systematic manner. Furthermore, the performance of embedment depth and time-dependent holding capacity for these nine DIAs was theoretically assessed using the well-established theoretical methods. In this study, two scenarios with identical impact velocity or embedment depth were examined; wherein the variation of holding capacity with reconsolidation time was explicitly accounted for. Based on the findings, practical implications of fin configurations were reached that may benefit the design of finned DIAs in practice.