Post-Installation Consolidation of Helical Anchors in Clay

Abstract Helical anchors have gained prominence as an innovative foundation solution for offshore wind applications in deep-water environments, owing to their high load-bearing capacity and installation efficiency. While substantial research has focused on the behavior of helical anchors during installation, the consolidation process in the surrounding soil post-installation remains insufficiently understood. Accurately predicting this consolidation behavior is crucial for ensuring long-term stability, as it directly influences load-bearing capacity and settlement over time. Conventional techniques, such as piezocone penetration tests (CPTu), provide valuable estimates of soil consolidation parameters; however, these methods are inherently limited in capturing the unique consolidation processes of helical anchors. This limitation arises from the geometric and load transfer differences between helical anchors—characterized by a central shaft and helices—and the simplified geometry of piezocones. To address this knowledge gap, this study presents centrifuge tests investigating the consolidation behavior of helical anchors installed with varying advancement ratios (ARs). The tests enable detailed monitoring of excess pore pressure dissipation in the soil surrounding the anchors. It was observed that the upper and lower surfaces of the helical plate exhibited distinct consolidation behaviors, and that AR < 1 may require a longer consolidation time to achieve full consolidation compared with AR = 1.0 (pitch-matched installation). These findings provide critical insights for refining helical anchor installation strategies, optimizing post-installation performance, and improving foundation designs for offshore wind energy systems in clayey soils.