Centre for Offshore Foundation Systems

Postgraduate research profiles

Contact

Chao Han

Phone: (+61 4) 3363 0516
Fax: (+61 8) 6488 1044


Start date

Jul 2012

Submission date

Jun 2015

Chao Han

Chao Han profile photo

Thesis

Investigation of Performance of Permanent Suction Embedded Plate Anchors

Summary

The suction embedded plate anchors (SEPLAs) are being used increasingly to moor large floating structures for development of hydrocarbon fields in deep and ultra-deep water. The installation of SEPLAs borrows concepts and techniques from conventional suction caissons, whilst the resistance to external loadings is provided by plate anchors deeply embedded into mud-line. Early applications of SEPLAs were confined to short-term offshore facilities, and their monotonic capacity has been extensively studied. Since the deployment of the first permanent SEPLA in 2006, a knowledge gap has been noticed regarding to its long-term performance against tides, storms, and loop currents.

The overall objective of this research is to explore the SEPLA performance for permanent mooring applications under sustained cyclic pulling loads in severe weather conditions, via the combination and comparison of numerical analyses and experimental testing data, currently available and to be devised, and to subsequently establish potentially more accurate approaches in predicting the anchor behavior, and assessing, as well, stability of the foundation system quantitatively. This goal can be achieved by solving the following problems:

i. to define the possible design loads that are imposed on the floating objects in typical loading conditions, and to transmit them onto the SEPLA at the padeye

ii. to numerically model soil’s stress-strain relationship, taking account for cyclic effect, consolidation and strain softening, and to reasonably reproduce the offshore loading situations

iii. to quantify the ultimate mooring capacity of the anchor imposed on various levels of sustained and cyclic loads

iv. to devise a series of laboratory tests (including characteristic tests of the soil and centrifuge scale model tests) in support of numerical predictions

v. to integrate all developed approaches into a SEPLA design system

Why my research is important

Contributions of addressing this research are in the following aspects:

• Gain knowledge on clay behaviour due to consolidation

• Future application of SEPLAs with confidence

• Successful research methodologies can be applied to similar problems

Funding

  • LRET scholarship top up
  • Australian Postgraduate Award