Macro-element modelling of time-dependent tensile behaviour of bucket foundation in normally consolidated clays

The tensile behaviour of bucket foundations in clays is strongly time dependent due to the combined effects of seepage and consolidation. Yet existing macro-element approaches are limited in capturing these processes. This paper presents a macro-element model for representing time-dependent uplift. The model integrates elastoplasticity and viscoplasticity to capture time-independent (undrained/fully drained) and time-dependent (partially drained) behaviour, with the viscoplastic component using an overstress approach relative to the drained limit. At variance with existing models, this novel framework allows the recovery of elastoplastic foundation response at both undrained and drained limits, with independent control over these limiting behaviours. In addition, the model accounts for time-dependent uplift from both seepage and consolidation, with the ability to independently control these mechanisms. Lastly, the model is expressed in normalised variables and characteristic load–displacement relations, enabling its application to different soil parameters without recalibration. Validation against finite-element simulations shows that the model reproduces uplift responses across a wide range of drainage conditions and loading histories. The model’s computational efficiency is assessed, showing that it runs several orders of magnitude faster than finite-element analyses.