Measured and calculated spudcan penetration profiles for case histories in sand-over-clay. (January 2019)

• Record Type: Journal Article
• Authors: Hossain, Muhammad Shazzad; Hu, Pan; Cassidy, Mark Jason; Menzies, David; Wingate, Audrey
• Is Part Of: Applied ocean research. Volume 82(2019)
• Page Start: 447
• Page End: 457
• Publication Date: 2019-01
• Subjects: Bearing capacity -- Clays -- Failure -- Footings/foundations -- Numerical modelling -- Offshore engineering -- Sands; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2018.10.027
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: Case histories of jack-up rig installation. Stronger sand layer overlaying a weaker clay layer. Measured continuous load-penetration profiles. Site-investigation data. Comparisons between measured data and profiles calculated using ISO guideline and recently proposed analytical calculation method. Abstract: This paper reports five case histories of jack-up rig installation in layered soil profiles where a dominate feature was a stronger sand layer overlaying a weaker clay layer. In all cases a relatively continuous load-penetration profile was measured during installation of each of the three spudcan foundations. Summary site-investigation data is provided and consisted of mainly torvane, minature vane, unconsolidated undrained triaxial and pocket penetrometer tests for determining undrained shear strength of the clays and blow counts for deriving the relative density of sand. A statistical averaging method recommended in the InSafeJIP guidelines was used to provide the best fit of the undrained shear strength profile in the clay as this then allowed for spudcan load-penetration profiles to be estimated without introduction of user interpretation or bias. Sand properties were taken as provided in the original site-investigation report. Comparisons between load-penetration profiles calculated using the industry-standard ISO guideline, more recently proposed mechanism-based calculation method and three-dimensional large deformation finite element simulations are made with the measured data, leading to valuable insights for practitioners for estimating behaviour of jack-up installations in problematic sand-over-clay soil profiles.