Numerical investigation to the cyclic loading effect on capacities of the offshore embedded circular foundation in clay

Abstract

The effect of cyclic loading on the bearing capacity is significant problem in the geotechnical design of offshore foundations. This paper proposes a combined isotropic and kinematic hardening soil model, where the components of stain rate and strain softening are introduced, as to investigate the cyclic loading effect on the capacity of the offshore embedded circular foundation. The proposed model is well implemented by the aid of subroutine USDFLD in the commercial software of ABAQUS. The model reliability to predict the degradation of soil strength is validated at the elementary and model scale levels, with typical model parameters provided. Then, the examination of strain softening mechanism of clayey soil surrounding the embedded circular foundation is made, with the evolution of soften soil region (including the pattern and dimensions) under the cyclic horizontal and moment loading investigated. By a suit of cyclic loading analyses, the post-cyclic capacities against the numbers of cycles are reported and evaluated, with the effect of magnitude of vertical loading on the cyclic loading capacities represented by the shrinkage of combined loading failure envelops.