Numerical investigations into the influence of drainage on the uplift behaviour of plate anchors in clay

This paper presents one of the first systematic finite element investigations into the rate effect during plate anchor uplift in clay, with a focus on the influence of soil drainage. Some numerical difficulties in simulating partially/fully drained anchor uplift are first discussed, and a method to address these issues is proposed. The most striking benefit of the proposed method is that it allows the hydro-mechanical coupled anchor-soil interaction to be efficiently simulated, with improved numerical stability, by simply using a non-detachable anchor-soil interface. After validation, the proposed method is used to simulate anchor uplift at different embedment and uplift rates, spanning from drained to fully undrained conditions. The influence of uplift rate on the force–displacement relations and failure mechanisms are discussed. The threshold rates to differentiate drained, partially drained, and undrained conditions are quantified. Anchor penetrations are also simulated under the same conditions. Comparisons with uplift cases indicate that the force–displacement curves in uplift and penetration are only identical in undrained conditions.