Changing soil responses during episodic cyclic loading in DSS tests
Changing soil responses during episodic cyclic loading in DSS tests
Whole life geotechnical design is an emerging philosophy in offshore geotechnical engineering to improve design outcomes by considering the whole life of imposed actions coupled with geotechnical properties that evolve with each action. Softening of normally consolidated clays from undrained cyclic loading intervened with consolidation has been shown to lead to hardening, manifested by evolving strength, stiffness, and coefficient of consolidation. This paper presents results from a set of stress-controlled direct simple shear (DSS) tests. The tests follow pre-failure episodic cyclic loading stress paths where each episode comprises a packet of undrained cycles of loads followed by full consolidation. The soil response under different numbers of cycles per loading packet and number of loading packets with intervening consolidation is investigated. The results from this study quantify the effect of the undrained cyclic loading history, for the same final number of cycles, on the evolution of the soil properties, to support the application of whole life geotechnical design in practice. Outcomes allow calibration of design curves that are traditionally used to capture softening, by introducing consolidation effects. This enables capturing the whole life softening and hardening processes, by extending the traditional contour diagram representation for undrained cyclic loading without consolidation to allow for consolidation periods.
Clay, Direct simple shear, Geotechnics, Offshore engineering
1441-1447
International Society of Offshore and Polar Engineers
Laham, Noor
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Kwa, Katherine
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Deeks, Andrew
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Suzuki, Yusuke
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White, David
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Gourvenec, Susan
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5 June 2022
Laham, Noor
d4af2376-9e9c-4b89-aa76-972f2b78fb0e
Kwa, Katherine
18faee0d-75d9-4683-a2c8-604625eecbb0
Deeks, Andrew
edd984b6-a70e-4575-8c6d-f9d52bb33380
Suzuki, Yusuke
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White, David
a986033d-d26d-4419-a3f3-20dc54efce93
Gourvenec, Susan
6ff91ad8-1a91-42fe-a3f4-1b5d6f5ce0b8
Laham, Noor, Kwa, Katherine, Deeks, Andrew, Suzuki, Yusuke, White, David and Gourvenec, Susan
(2022)
Changing soil responses during episodic cyclic loading in DSS tests.
In Proceedings of the 32nd International Ocean and Polar Engineering Conference, ISOPE 2022.
International Society of Offshore and Polar Engineers.
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
Whole life geotechnical design is an emerging philosophy in offshore geotechnical engineering to improve design outcomes by considering the whole life of imposed actions coupled with geotechnical properties that evolve with each action. Softening of normally consolidated clays from undrained cyclic loading intervened with consolidation has been shown to lead to hardening, manifested by evolving strength, stiffness, and coefficient of consolidation. This paper presents results from a set of stress-controlled direct simple shear (DSS) tests. The tests follow pre-failure episodic cyclic loading stress paths where each episode comprises a packet of undrained cycles of loads followed by full consolidation. The soil response under different numbers of cycles per loading packet and number of loading packets with intervening consolidation is investigated. The results from this study quantify the effect of the undrained cyclic loading history, for the same final number of cycles, on the evolution of the soil properties, to support the application of whole life geotechnical design in practice. Outcomes allow calibration of design curves that are traditionally used to capture softening, by introducing consolidation effects. This enables capturing the whole life softening and hardening processes, by extending the traditional contour diagram representation for undrained cyclic loading without consolidation to allow for consolidation periods.
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Published date: 5 June 2022
Additional Information:
Funding Information:
This study forms part of the activities of the Royal Academy of Engineering Chair in Emerging Technologies Centre of Excellence for Intelligent & Resilient Ocean Engineering (IROE) at the University of Southampton through a collaboration project “Characterization of Geotechnical Properties for Whole Life Design” with the Norwegian Geotechnical Institute (NGI). Financial support of the Norwegian Research Council under their basic funding program for NGI is acknowledged. Susan Gourvenec is supported by the Royal Academy of Engineering under the Chairs in Emerging Technologies scheme. Katherine Kwa and David White are supported by the EPSRC Offshore Renewable Energy Supergen Hub (EPSRC grant EP/S000747/1).
Publisher Copyright:
© 2022 The International Society of Offshore and Polar Engineers (ISOPE). All rights reserved.
Venue - Dates:
32nd International Ocean and Polar Engineering Conference, ISOPE 2022, , Shanghai, China, 2022-06-05 - 2022-06-10
Keywords:
Clay, Direct simple shear, Geotechnics, Offshore engineering
Identifiers
Local EPrints ID: 473766
URI: http://eprints.soton.ac.uk/id/eprint/473766
ISSN: 1098-6189
PURE UUID: 6fba186f-9007-49e4-b9a3-dee2f6b63b54
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Date deposited: 31 Jan 2023 17:41
Last modified: 18 Mar 2024 03:52
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Contributors
Author:
Andrew Deeks
Author:
Yusuke Suzuki
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