Plate anchors for offshore foundations in sand and clay
type: CreativeWork
description: As the offshore wind industry moves into areas of deeper water, traditional foundation structures such as monopiles will become less economically feasible. This has generated a push for the development of floating turbines, which are held in place by mooring lines with anchor foundations in the seabed. As a result, the development of anchor foundation concepts, which can resist large vertical and horizontal loads have become a focus of research in recent years. Due to the varying ground conditions encountered in the offshore environment, various types of anchors have been developed. This thesis reports the findings of laboratory based investigations into the installation and loading behaviour of two novel plate anchor foundation concepts. The concept for a Bi-wing Anchor which can be dropped through the water column and penetrate into the seabed under its own weight was introduced. After dropping, the anchor could then be dragged, causing it to embed further into the seabed. This would allow the anchor to be installed more quickly and to greater embedment depths than conventional drag-in plate anchors. Physical modelling was used to analyse the drag behaviour of this anchor. Tests were completed in a transparent clay surrogate, which was consolidated through the application of a pressure gradient across the sample‟s depth. The observations from these tests were used in the development of an analytical model for drag embedment. The analytical predictions showed good agreement with the observed anchor behaviour at multiple embedment ratios. The ultimate capacity of the anchor during pullout was analysed through centrifuge modelling in normally consolidated kaolin clay. The effect of the anchor‟s shape on its pullout capacity was analysed by varying the space between two anchor flukes in a series of tests. The anchor shape had minimal effect on deep and intermediate soil failure mechanisms. For shallow failure mechanisms, increasing the spacing between the flukes resul…
abstract: As the offshore wind industry moves into areas of deeper water, traditional foundation structures such as monopiles will become less economically feasible. This has generated a push for the development of floating turbines, which are held in place by mooring lines with anchor foundations in the seabed. As a result, the development of anchor foundation concepts, which can resist large vertical and horizontal loads have become a focus of research in recent years. Due to the varying ground conditions encountered in the offshore environment, various types of anchors have been developed. This thesis reports the findings of laboratory based investigations into the installation and loading behaviour of two novel plate anchor foundation concepts. The concept for a Bi-wing Anchor which can be dropped through the water column and penetrate into the seabed under its own weight was introduced. After dropping, the anchor could then be dragged, causing it to embed further into the seabed. This would allow the anchor to be installed more quickly and to greater embedment depths than conventional drag-in plate anchors. Physical modelling was used to analyse the drag behaviour of this anchor. Tests were completed in a transparent clay surrogate, which was consolidated through the application of a pressure gradient across the sample‟s depth. The observations from these tests were used in the development of an analytical model for drag embedment. The analytical predictions showed good agreement with the observed anchor behaviour at multiple embedment ratios. The ultimate capacity of the anchor during pullout was analysed through centrifuge modelling in normally consolidated kaolin clay. The effect of the anchor‟s shape on its pullout capacity was analysed by varying the space between two anchor flukes in a series of tests. The anchor shape had minimal effect on deep and intermediate soil failure mechanisms. For shallow failure mechanisms, increasing the spacing between the flukes resul…
author: Fanning, Joseph
language: eng
keywords: sand, clay, model test
date published: 2020-7
date modified: 2026-07-24T03:55:25Z
provider: Queen's University Belfast
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Queen's University Belfast