A study has been performed as part of a software development process to assess penetration resistance of jack-up spudcan in multi-layered systems (≥ 3 layers). A general design algorithm is proposed, based on the single or two-layer methods adopted commonly in practice, aimed at solving the spudcan penetration problem in soils with three or more layers. The proposed algorithm has also been verified against published data including complex stratified soil profiles. In general, the calculated spudcan load-penetration profile shows good agreement with the reported results. Potential punch-through and soil squeezing are reasonably predicted.
Prior to the installation of a mobile jack-up spudcan, an assessment is needed to confirm the depth of penetration under preload, and to identify any punch-through risk (SNAME, 2002). This applies not only to drilling rigs used in the oil and gas industry, but also to the many re-locations needed for jack-ups working in the offshore wind energy sector to place wind turbine structures. The jack-up spudcan foundation usually has an inclined base with a conical tip, which makes it different from the flat footing. However, the solutions for flat footings are usually employed to assess the penetration resistance of spudcans, as suggested in SNAME (2002). Many of these solutions are found to give reasonable results (Menzies and Roper, 2008). In reality, there is an infinite variety of soil profiles, and a literature review reveals that the footing bearing capacity in single and two-layer system has been widely investigated. For example, Brinch Hansen (1970), Houlsby and Martin (2003) and Hossain et al. (2006) studied the footing capacity in single clay or sand layer; while Meyerhof and Chaplin (1953), Meyerhof and Hanna (1978) and Teh et al. (2009) provided solutions for two-layer system, aiming at identifying soil squeezing or punch-through mechanisms.