Jack-up push-over analyses featuring a new force resultant model for spudcans in soft clay

Abstract With the development of the offshore oil and gas industry, mobile jack-up drilling platforms are increasingly utilized in deeper waters and harsher environments. Excessive conservatism in jack-up site specific assessment may result in undue rejection of a unit. In soft clayey seabeds, the spudcan foundations of the jack-up platform penetrate deeply into the soil with partial or complete backflow. Although the deep penetration and associated backflow are widely perceived to increase horizontal and moment foundation bearing capacities in particular, the problem is not well understood. In this paper therefore, a plasticity foundation model is proposed that accounts for the effects of backflow. It has been developed through a combined numerical and experimental study. The model is suitable for performing integrated soil–structure analyses. Results of such analyses of a jack-up under quasi-static push-over load are discussed to highlight the impact of the model in the context of site specific assessment of jack-up rigs in soft clay.

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