Stefanus Safinus

Thesis

Estimation of spudcan penetration resistance in layered soils directly from field penetrometer data and quantification of punch-through risk

Summary

Punch-through incidents of offshore mobile drilling rig, often occur during jacking, mostly attributable to inadequate site investigation or geotechnical assessment. Combining field data from industry partner and physical modelling, a robust method to evaluate the spudcan performance in multi-layered soils directly from penetrometer data will be developed. This project concentrates especially on the penetration in carbonate deposit, which is often encountered around Australia.

First, an automated approach for interpretation of soil layering and relevant strength properties from continuous cone penetration data will be developed. Then, by incorporating the existing solutions for single- and two-layer soils, a universal approach to predict the spudcan penetration resistance in multi-layered soil profiles will be developed. The resulting penetration resistance profile will serve as the basis to assess the potential for spudcan punch-through and its likely severity. At last, this procedure will be verified through field data and physical centrifuge modelling.

Why my research is important

A complete reliance on penetrometer data in evaluating the spudcan penetration will allow an early and accurate planning of damage mitigation response during the jack-up installation. The direct use of the field data also eliminates the uncertainty which often shadows the laboratory test due to the disturbance of samples recovered from the seabed. The result of this research will allow a safer and economic installation of jack-ups in Australian water and support the expansion of offshore exploration industry.

Funding

• Scholarship for International Fees Research (SIRF)
• University International Stipend (UIS)
• The Lloyd’s Register Education Trust (LRET) PhD Top Up Scholarship
• Australian Research Council Linkage Grant and Keppel Offshore and Marine, Singapore