Geotechnical challenges in monopile foundations and performance assessment of current design methodologies
Sachin Jindal, Ulvi Rahmanli, Muhammad Aleem, Liang Cui, Subhamoy Bhattacharya
Abstract
This research comprises an in-depth review of monopile foundations for offshore wind turbines under monotonic and cyclic loads. The review study was complemented with performance evaluation of the current design methodologies using advanced finite-element analyses. Overview of intricate nature of pile-soil interactions conducted yielded inadequacy of conventional monotonic p-y curves, which were historically tailored for the oil and gas industry. The paper dives into the effects of cyclic loads on soil stiffness around monopile foundations which indicated dissensus in the scientific community. In the realm of soil damping for monopile foundations, the study underscores the complexities of damping and the general neglect of directly calculated soil damping ratio. Performance assessment of various design methodologies is central to this research. By comparing the conventional API p-y curves, the PISA design method, and the new ISO/API p-y curves with three-dimensional finite element analyses, a discerning evaluation emerges, pinpointing the strength and drawbacks of the current engineering methodologies. Overall, the study concludes the pressing need for refined, evidence-based geotechnical strategies in the realm of monopile foundation design and assessment.