The post-installation consolidation settlement of jack-up spudcan foundations in clayey seabed soils

• Published in: Computers and geotechnics Vol. 123; p. 103611
• Main Authors: Yi, Jiang Tao, Pan, Yu Tao, Qiu, Zi Zhan, Liu, Fei, Zhang, Xi Ying, Zhang, Lei
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.07.2020; Elsevier BV
• Subjects: Centrifuge modelling; Centrifuges; Consolidation; Consolidation settlement; Deformation; Deformation effects; Drainage effects; Feasibility studies; Jackup platforms; Large deformation finite element analyses; Mathematical analysis; Ocean floor; Offshore; Offshore drilling rigs; Offshore engineering; Operators; Soil; Soil settlement; Spud-can foundations; Spudcan foundation; Consolidation settlement; Offshore engineering; Spudcan foundation; Large deformation finite element analyses; Centrifuge modelling
• ISSN: 0266-352X; 1873-7633
• DOI: 10.1016/j.compgeo.2020.103611

The post-installation consolidation settlement of spudcan foundations is an issue of concern for the offshore jack-up industry, especially when jack-up rigs operate for long periods. Although there are field records of excessive spudcan settlement during the rig operation, there are no guidelines available for operators to assess and project the consolidation settlement development. This paper reports a study dedicated to this specific subject. The spudcan installation and consolidation under operational load were continually modelled using an effective-stress large deformation finite element technique. The feasibility and reliability of the numerical calculation were first verified by comparison with centrifuge experiments. Parametric studies were then undertaken for spudcans under various soil, loading, embedment and geometrical conditions, so as to identify appropriate forms of dimensionless settlement and time which can unify the settlement time histories of different scenarios. Particular attention was paid to the development of the dimensionless time, which can reflect the drainage effect of the seabed and hence the influence of embedment depth. The unified settlement development curve may be helpful for operators to assess the consolidation degree, project the final settlement and even back-calculate the operative coefficient of consolidation.