Clay strength re-gain following cycling and consolidation – application to suction caisson foundations-Part II

N. Hamdan, B. M. Lehane, T. A. Powell, T. Joseph, Larry E. Jones

Research output: Chapter in Book/Conference paperConference paperpeer-review

Abstract

Suction caissons have recently become a popular foundation type for offshore renewable structures. They are usually installed by creating differential internal pressure to embed the foundation to its target penetration. The required installation pressure depends on the soil resistance, submerged weight of caisson and its geometry. Installation pressure can be reduced when adopting two-way pressure cycling. This process involves cycling the pump flow rate to cause small upward and downward movements of the caisson which soften the clay strength along the shaft hence reducing the required pressure for installation. This paper presents results from a suite of cyclic simple shear (CSS) tests which was conducted to gain understanding of the effects of cycling on the strength of clay samples and the subsequent strength re-gain with time. Soil samples were subjected to 10 two-way cycles, consolidated for various periods of time and monotonically sheared. Soil strengths post-cycling and consolidation were measured. Results indicated that the soil strength is fully recovered at laboratory scale. Recommendations on the effect of the applied two-way cycling on clay samples and subsequent strength post-cycling re-gain are drawn. The paper concludes on practical application of results and implication on cyclically installed suction caissons for the Offshore Renewable Sector.

Original languageEnglish
Title of host publicationOffshore Site Investigation Geotechnics 9th International Conference Proceeding
PublisherSociety for Underwater Technology
Pages1733-1740
Number of pages8
ISBN (Print)9780906940594
DOIs
Publication statusPublished - 2023
Event9th International Conference on Innovative Geotechnologies for Energy Transition, 2023 - London, United Kingdom
Duration: 12 Sept 202314 Sept 2023

Publication series

NameOffshore Site Investigation and Geotechnics
ISSN (Print)2754-6322

Conference

Conference9th International Conference on Innovative Geotechnologies for Energy Transition, 2023
Country/TerritoryUnited Kingdom
CityLondon
Period12/09/2314/09/23

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