Rubble-mound Structure Design In The Coastal Environment

"The main aims of this thesis were to investigate the main aspects of the design and implementation of rubble-mound structures as a form of shoreline stabilisation and coastal defence. An emphasis has been placed on the Irish context of how these structures have been implemented in the past. The intention was that this work would improve the understanding of the use of these structures for future projects both in Ireland and internationally. This work required a literature review which investigated the general aspects of rubble-mound structures, the coastal environment, and the theory of designing the structures’ layout, cross-section and impact upon the local shoreline as well as the subsequent environmental, economic and social impacts such a project might have. Furthermore detailed case studies have been undertaken on beaches in Ireland where rubble-mound beach stabilisation structures have been proposed or implemented. A computer programme has been developed capable of designing the structural layout and cross section for two forms of rubble-mound shoreline stabilisation structures, namely offshore breakwaters and groynes. The Rubble-mound Structure Analysis and Design System is also capable of predicting the shoreline response and the carbon footprint and cost of both structural systems. This system is based on the information presented in the literature review. RSADS has facilitated a detailed study into the sizing of Rubble-mound structure armour units which are the primary structural element of this form of coastal defence. This work has culminated in a detailed study of Youghal Beach in County Cork. This study has involved a beach level survey, and a detailed review of the coastal processes and existing coastal structures. Coastal structures which have been proposed for Youghal by Malachy Walsh & Partners have also been reviewed. Finally RSADS has been implemented to carry out a full design for the shoreline at Youghal resulting in a final proposal of a rock armoured rubble-mound groyne field. Finally the conclusions on the work carried out, future work and the topic in general are presented in the final chapter of this thesis."