Foundation Modeling and Assessment in the New ISO Standard 19905-1

摘要

This paper presents the new foundation assessment provisions in ISO 19905-1. The paper discusses the improvements tornspudcan penetration analysis achieved by the refinement of bearing capacity formulations and by adoption of a fundamentallyrnnew approach to backflow prediction which accounts for the changes in soil flow regime and the evolving pattern of soilrndeformation in the vicinity of the spudcan. It also addresses the upgrades made to the SNAME 5-5A approach to foundationrncapacity and foundation stiffness reduction in sand and clay as well as the means used to better account for the effects of deeprnspudcan penetrations in clay. The change to, and basis for, the use of gross foundation capacity in some of the calculationsrnare also discussed. Finally, the paper presents the new foundation acceptance checks framework consequent to the changernfrom available capacity/reaction concept in SNAME 5-5A to gross capacity/reaction approach in ISO 19905-1.rnAt the time of this paper submission, it was expected that ISO 19905-1 would be isssued prior to the presentation of the paperrnat the 2012 Offshore Technology Conference. Upon the issue of this standard the new foundation assessment provisionsrndescribed in this paper will be required for jack-up site-specific assessments worldwide.