Article ID Journal Published Year Pages File Type
1720514 Applied Ocean Research 2006 13 Pages PDF
Abstract

This paper presents an improved numerical ‘force resultant model’ for spudcan foundations that can be used within a structural analysis of a mobile drilling unit. The model incorporates hysteretic behaviour for pre-yield ‘elastic’ movements by using a hyperplasticity formulation [Houlsby GT, Puzrin AM. Rate-dependent plasticity models derived from potential functions. Journal of Rheology 2002;46(1):113–26] for the moment–rotation response in the ‘elastic’ stiffness matrix. The formulation is embedded within an existing single surface plasticity model [Martin CM, Houlsby GT. Combined loading of spudcan foundations on clay: Numerical modelling. Géotechnique 2001;51(8):687–99] that would typically use linear elastic stiffness coefficients. The hyperplastic model has been calibrated against single footing tests carried out using a sophisticated three degree-of-freedom loading device at Oxford University. These loading tests were specific to the load paths experienced by spudcan foundations of large jack-ups in deep water. Further experimental work at the University of Western Australia involved applying monotonic and cyclic loading to a model three-legged jack-up [Vlahos G. Physical and numerical modelling of a three-legged jack-up structure on clay soil. Ph.D. thesis. Australia: University of Western Australia; 2004; Vlahos G, Martin CM, Prior MS, Cassidy MJ. Development of a model jack-up unit for the study of soil–structure interaction on clay. International Journal of Physical Modelling in Geomechanics 2005;5(2):31–48]. The experimental results from jack-up tests were compared to numerical simulations using a finite element model with the single surface plasticity foundation model incorporating (i) linear springs, and (ii) non-linear hyperplastic springs. The latter formulation showed an improved correlation with the experimental results.

Related Topics
Physical Sciences and Engineering Engineering Ocean Engineering
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