Macro-Element Modelling of Plate Anchor Kinematics under Cyclic Loading in Clay-Paper

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The paper develops a macro-element model to simulate plate-anchor behaviour in clay under cyclic loading. Building on an earlier non-associative model for monotonic loading, it modifies the hardening rule and plastic-flow direction to represent repeated loading and unloading. The approach offers a computationally efficient alternative to extensive centrifuge testing or three-dimensional finite-element analysis.<br /><br />The model first shows good agreement with finite-element results for monotonic anchor keying across a range of padeye offsets. Cyclic simulations then examine how load amplitude and cycle count affect anchor rotation, displacement and post-cyclic pull-out capacity. In the model, cyclic loading progressively reorients the anchor, changing the distribution of forces acting on it and shifting its load path toward the centre of the strength surface. Consequently, the anchor reaches its peak resistance later and at a lower load than under monotonic loading.<br /><br />Predicted post-cyclic peak capacity decreases as either the number of cycles or cyclic load amplitude increases. Higher amplitudes produce faster capacity loss during the initial cycles, while displacement accumulation depends on amplitude: it tends to stabilise for smaller cyclic loads but continues to grow for larger ones. Reorientation also increases anchor rotation and horizontal movement.<br /><br />The findings indicate that cyclic capacity loss can result not only from changes in soil strength, but also from the anchor’s evolving kinematics. The model does not yet account for pore-pressure generation, consolidation or soil destructuration. Its calibration for cyclic conditions—and the applicability of parameters derived from monotonic tests—also requires further investigation.

Keywords

plate-anchor

clay

cyclic loading

macro-element model

non-associative model

hardening rule

plastic-flow direction

anchor rotation

post-cyclic capacity

finite-element analysis