Undrained capacity of skirted circular foundations under fully three-dimensional loading

Skirted circular foundations are widely used in offshore engineering, which are subjected to fully threedimensional loading caused by environmental and operational loads. In this study, finite-element limit analysis was employed to explore the undrained capacities of skirted circular foundations at varying embedment ratios and soil strength heterogeneity indices under fully three-dimensional loading. The ultimate limit state of a foundation was described by the failure envelope in the normalised H-M loading plane considering vertical and torsional load mobilisation. The effects of embedment ratio, soil strength heterogeneity index, loading angle, vertical load and torsion on the normalised failure envelopes were discussed. Several equations were proposed to describe the ultimate uniaxial capacities and failure envelopes of skirted circular foundations under different loading combinations. These equations can be used for the initial foundation design. An example was presented to illustrate the application procedure of the proposed equations in foundation design.

Automated summary

Finite-element limit analysis was used to study the undrained capacities of skirted circular foundations under fully three-dimensional loading. The failure envelope in the normalised H-M loading plane was described to represent the ultimate limit state of the foundations. The effects of various factors on the failure envelopes were discussed. Equations were proposed to describe the uniaxial capacities and failure envelopes of skirted circular foundations under different loading combinations, which can be used for initial foundation design. An example was presented to illustrate the application procedure of the proposed equations.