Deterministic and probabilistic advances in the analysis of spudcan behaviour

![CDATA[This paper presents recent advances in the prediction of the installation of jack-up platforms. New analytical models for spudcan installations in clays, sand-over-clay and stiff-over-soft clays are reviewed and compared to the existing methods in the recently released ISO 19905-1 standard. The ability of each to retrospectively simulate databases of field and centrifuge model tests are summarised and conclusions are drawn on whether or not modifications to the ISO document are warranted. The paper also demonstrates how deterministic approaches commonly used in jack-up assessment can be transformed into and completed by probabilistic predictions. Prior predictions of jack-up installations can be improved with the use of model factors obtained from existing field records or model tests. Curves of jack-up installation pressure versus depth can be written as probability of exceedance curves, thus providing the engineer with information on how the installation curve may develop.ABayesian updating technique is introduced and provides a reliable and consistent framework to update installation predictions with monitored information. This technique is then applied to predict punchthrough potential in layered soils. Hypothetical examples demonstrate how updated quantitative information can benefit industry in guiding decisions during offshore jack-up installations. The authors hope that the introduction of the probabilistic approaches, although less mature than the deterministic ones, will provoke discussion and suggest a path forward for the jack-up industry.]]