Page 41: of Offshore Engineer Magazine (Mar/Apr 2015)

40 42

parameter selection is required to account the seabed or on engineered structures in This article is based on a longer paper

EPIC for uncertainty in the effect of cyclic response to thermally-induced expansion Frontiers in Deepwater Geotechnics: loading on engineering parameters, which during operation (OE: April 2014). Optimizing Geotechnical Design of will lead to conservatism in design output. Subsea Foundations by Susan Gourvenec

Conclusion

Current work at COFS is investigating a and Xiaowei Feng, published in a special framework to predict cyclic degradation of A tool box of solutions to optimize the edition of Australian Geomechanics, soil properties, with particular attention geotechnical aspects of subsea founda- December issue, 49(4). to subsea mudmats. Foundation capacity tion design has been highlighted. The

Susan Gourvenec is a could then be assessed by accounting for various options can be described by

Professor at the Centre consolidated gains in capacity, modifed an ‘optimization class’ in terms of (1) for Offshore Founda- by a reduction factor to account for cyclic optimizing the design methodology, tion Systems at the loading degradation. (2) optimizing the confguration of the

University of Western foundation, (3) optimizing the geotechni-

Optimization of operational mode

Australia. Gourvenec cal input parameters and (4) optimizing

Challenging the traditional but conserva- the mode of operation. The techniques has more than 15 years tive paradigm that a foundation should described are examples of some tools of geotechnical remain stationary, optimization can be in each class, but the implication is not engineering experience, with particular achieved through tolerable foundation that the tool box is complete. Much interest in offshore geotechnics. She is a mobility. scope exists for adding new tools in each consultant offshore geotechnical engineer

The concept of mobile foundations is class. Current research at the Centre to industry and member of the ISO and API that they are designed to move tolerably for Offshore Foundation Systems at the

Committees for Offshore Geotechnics. across the seabed to absorb some of the University of Western Australia is inves- load imposed by thermal expansion of tigating new tools for predicting cyclic

FURTHER READING the pipeline rather than being designed load response and settlements – tools large enough to resist all the operational that are simple enough to use but sophis-

Mobilizing subsea loads and remain stationary. The concept ticated enough to capture the necessary foundations. http://www.

of mobile foundations is radical, but a aspects of soil behavior. Many of the oedigital.com/energy/ logical progression from the now widely- technologies described in this paper have renewables/item/5474- accepted practice of permitting subsea been applied in practice supporting proj- mobilizing-subsea-foundations pipelines to buckle laterally either across ects offshore Australia and globally. 

Custom

REPRINts

Take Advantage of your Editorial Exposure

Marin provides comprehensive

Give yourself a competitive specialist services in the areas

Nobody of full ocean depth excavation, advantage with reprints. use this logo on white or lighter recovery, decommissioning, backgrounds drilling and offshore support.

does it

Call us today!

With a strong bias towards oil and gas frontiers, delivering complete solutions on complex projects deeper in the toughest and harshest of locations globally, Marin’s technology is cutting edge with specialists that thrive on solving deepwater use this logo on black or darker challenges.

backgrounds. The Printing

Service is in white.

Downhole Subsea Offshore

Solutions Intervention Support

For additional information, please contact Foster

Printing Service, the official reprint provider for

OE.

Subsea without limits.

marinsubsea.com

C: 56

M: 0

Call 866.879.9144 or

Y: 100

K: 27 [email protected]

PMS 370 C oedigital.com March 2015 | OE 43

Marin_85x123_advert_Final.indd 1 20/01/2015 11:58 040_OE0315_EPIC2_COFS_em1.indd 43 2/23/15 12:21 PM