Influence of Structural Elements on the Spatial Sediment Displacement around a Jacket-Type Offshore Foundation

verfasst von

Mario Welzel, Alexander Schendel, Nils Goseberg, Arndt Hildebrandt, Torsten Schlurmann

Abstract

This research advances the understanding of jacket-type platform induced local and global erosion and deposition processes for combined wave-current conditions. To this end, a laboratory study was carried out comparing the equilibrium scour depth for two structural designs that are differentiated in the geometrical distance of the structure's lowest node to the seabed. Measurements of local scour depths over time have been conducted with echo sounding transducers. An empirical approach is proposed to predict the final scour depths as a function of the node distance to the seabed. Additionally, 3D laser scans have been performed to obtain the digital elevation model of the surrounding sediment bed. Novel methodologies were developed to describe and easily compare the relative volume change of the sediment bed per surface area due to structure-seabed interaction, enabling spatial analyses of highly complex erosion and deposition patterns. The seabed sediment mobility around the structure is found to be highly sensitive to a change in node distance. The decrease of the node distance results in a higher erosion depth of sediment underneath the structure of up to 26%, especially for current-dominated conditions, as well as an increased deposition of sediment downstream of the structure over a distance of up to 6.5 times the footprint length. The results of this study highlight the requirement to consider the interaction of the structure with the surrounding seabed within the design process of offshore structures, to mitigate potential impacts on the marine environment stemming from the extensive sediment displacement and increased sediment mobility.

Organisationseinheit(en)

Ludwig-Franzius-Institut für Wasserbau, Ästuar- und Küsteningenieurwesen

Externe Organisation(en)

Technische Universität Braunschweig

Typ

Artikel

Journal

Water (Switzerland)

Band

12

Anzahl der Seiten

22

ISSN

2073-4441

Publikationsdatum

09.06.2020

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Biochemie, Geografie, Planung und Entwicklung, Aquatische Wissenschaften, Gewässerkunde und -technologie

Ziele für nachhaltige Entwicklung

SDG 14 – Lebensraum Wasser

Elektronische Version(en)

https://doi.org/10.3390/w12061651 (Zugang: Offen)