CUED Publications database

New evidence for the origin and behaviour of deep ocean 'crusts'

Kuo, MY-H and Bolton, MD and Hill, AJ and Rattley, MJ (2011) New evidence for the origin and behaviour of deep ocean 'crusts'. Frontiers in Offshore Geotechnics II - Proceedings of the 2nd International Symposium on Frontiers in Offshore Geotechnics. pp. 365-370.

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Abstract

In situ tests in deep waterWest African clays show crust-like shear strengths within the top few metres of sediment. Typical strength profiles show su rising from mud-line to 10 kPa to 15 kPa before dropping back to normally consolidated strengths of 3 kPa to 4 kPa by 1.5m to 2m depth. A Cam-shear device is used to better understand the mechanical behaviour of undisturbed crust samples under pipelines. Extremely variable peak and residual shear strengths are observed for a range of pipeline consolidation stresses and test shear rates, with residual strengths approximating zero. ESEM of undisturbed samples and wet-sieved samples from various core depths show the presence of numerous randomly-located groups of invertebrate faecal pellets. It is therefore proposed that the cause of strength variability during shear testing and, indeed, of the crust's origin, is the presence of random groups of faecal pellets within the sediment. © 2011 Taylor & Francis Group, London.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 12:03
Last Modified: 08 Dec 2014 02:40
DOI: