Bearing capacity of shallow foundations in clay with linear increase in strength and adhesion factor

In this paper, the computational lower bound (LB) limit analysis using finite element with second-order cone programming was used to investigate the LB solutions of the undrained bearing capacity of continuous footing with a linear increase in the strength profile and an adhesion factor at the soil–footing interface. A full range of parametric studies of the dimensionless strength gradients and adhesion factors at the soil–footing interface were performed in the LB calculations. The results were verified by comparison with the available solution from the method of characteristics (slip-line analysis) for perfectly smooth and rough footings. The LB analyses were able to complete a prior solution of undrained bearing capacity with a linear increase in the strength profile by incorporating the influence of adhesion factor at the soil–footing interface. Based on the nonlinear regression to the computed LB solutions, an approximate expression of the LB solution regression was proposed, which is applicable to an accurate prediction of a safe load for offshore shallow foundations in clay with an arbitrary linear increase in strength and adhesion factor at soil–foundation interface in practice.