Australian Research Council Centre of Excellence Geotechnical Science and Engineering

Mr Youhu Zhang

Supervisors

  • Assistant Professor Britta Bienen
  • Winthrop Professor Mark Cassidy

Research Interests

  • Offshore foundations
  • Combined VHM loading
  • Finite element modelling

Research Topic

A force resultant footing model for spudcan foundations in soft clay

Research Abstract

A jack-up platform is often moved to a new location once operation in one site is finished. However, before a jack-up platform can be deployed at a new site, a site-specific assessment has to be carried out, which assess the suitability of the platform under expected maximum loads at that location. This requires knowledge of the platform’s spudcan foundation-soil interaction behaviour, which includes both the spudcan foundations’ combined bearing capacity and their stiffnesses. Force resultant footing models are the current state of the art for describing foundation-soil interaction. However, for spudcan footings in soft clay soil, in which spudcan can penetrate deeply and soils flow back, refilling the cavity, the combined bearing capacity of spudcan foundations is not clear and no complete force resultant footing is available so far. This research is therefore to investigate the combined bearing capacity of spudcan foundations in soft clays, accounting for the effects of deep penetration and soil backflow. Based on the results of this study, a force resultant footing model for jack-up applications in soft clay seabed will be developed.

Why my research is important

This research will provide numerical and experimental evidence on the combined bearing capacity of spudcan foundations deeply embedded in soft clay soil. It will helps to avoid the excessive conservatism in the current industry guidelines that the combined bearing capacity of deeply embedded spudcan foundations are evaluated based methods appropriate for shallow penetrations. The final product of this research: the force resultant plasticity footing model will provide a useful foundation modelling tool to the industry when performing site specific assessment of jack-up rigs in offshore soft clay soils.

Funding

  • Scholarship for International Research Fees (SIRF)
  • University International Stipend (UIS)
  • Ad-hoc ‘Safety Net’ Top-up
  • Australia-China Natural Gas Technology Partnership Fund Top-up