Undrained uplift capacity of deeply embedded strip anchors in non-uniform soil

This paper presents new theoretical predictions of the undrained uplift capacity of deeply embedded inclined strip anchors in a soil stratum with a linear variation of strength with depth. Rigorous bounds on the theoretical uplift capacity are presented using upper and lower bound limit analysis. The effects of the strength gradient on the normalized uplift capacity and the predicted failure mechanisms are analyzed. Overall, the effect of the strength gradient on the capacity is shown to be rather small (less than 16% for the range of strength gradients considered), while the influence of the gradient on the failure mechanism can be significant. It is shown that the coupled effects of anchor inclination and the strength gradient are well characterized by formulae that provide a simple means for refining uplift calculations in practical applications.