Helical anchors are deep foundation systems that offer high uplift capacity due to the increased interaction area between the helix and surrounding soil, thus exhibiting strong potential for resisting frost jacking in cold-region engineering. The influence of helical anchor geometry on frost heave behavior remains a critical yet insufficiently understood factor in engineering designs. Accordingly, this study conducts experimental and numerical investigations to evaluate the effects of helix number, helix diameter, helix spacing, and freeze-thaw cycles on frost jacking and thaw-induced settlement. The results indicate that the frost jacking and residual displacement after thawing gradually decrease with increasing freeze-thaw cycles and tend to stabilize after more than three cycles. Numerical simulations show that the residual displacements for full-scale anchors range from 12% to 33% of the peak frost jacking. Anchors with a greater number of helices demonstrate improved resistance to frost jacking when the uplift capabilities are comparable. When the helix spacing ranges from 2D to 6D (where D denotes the helix diameter), the double-helix anchor with 2D spacing exhibits the highest stability during freeze-thaw cycles, followed by the anchor with 3D spacing. However, the anchor with 2D spacing yields the lowest uplift capacity under unfrozen soil conditions. Anchors with a helix spacing of 2D to 3D are recommended for resisting freeze-thaw effects, provided that this configuration does not significantly reduce the uplift capacity.

Upscaled screw piles have been proposed as anchors for offshore floating wind applications, but this upscaling can result in a significant increase in vertical installation forces. Previous studies have shown that the use of overflighting techniques during installation (installation advancement ratio, AR<1.0) can reduce or eliminate these forces and improve the capacity and stiffness of screw piles under monotonic tensile loading conditions. However, the impact of overflighting installation on the cyclic response of screw piles has not received adequate attention. To address this, a series of drained cyclic uplift tests in a geotechnical centrifuge were conducted. The tests involved different AR values during installation and varying one-way cyclic tensile loading amplitudes. The results revealed that reducing the installation AR can significantly decrease displacement accumulation and improve cyclic loading stiffness, resulting in a more stable cyclic response. The cyclic axial loading stiffness tends to stabilize or slightly decrease with cycling for stable cases, while unstable and metastable cases exhibit an initial reduction of loading stiffness followed by a stabilization or slow recovery. The postcyclic monotonic uplift tests also show that capacity degradation was predominately due to the displacement accumulation itself rather than any additional cyclic effects. The cyclic stability of the screw pile investigated was found to be comparable with straight-shafted and screw piles from previous studies and beneficial installation effects were maintained under cyclic loading. A predictive framework for displacement accumulation and capacity degradation is also presented and developed within this paper.