<![CDATA[This study assesses and compares the performance of single-helix and double-helix anchors in reinforcing geofoam embankments against uplift loads in sapric peat. Uplift instability is an important geotechnical concern for lightweight embankments constructed in peatland areas, particularly under groundwater fluctuations. The study combined laboratory-scale pull-out tests conducted in a cylindrical tank 58 cm in diameter and 98 cm in height with three-dimensional finite element analysis using PLAXIS 3D. The experimental program evaluated anchor load–displacement behavior, while the numerical analysis was used to examine displacement patterns and stress distributions around the anchor systems. Peat properties were determined using standard laboratory tests, and the geofoam material was specified in accordance with ASTM D6817. The double-helix configuration achieved a peak pull-out capacity of 1.45 kN, which was 31.8% higher than the 1.10 kN capacity of the single-helix configuration, and reached peak resistance at a 22.2% lower displacement. At the design uplift load of 7.5 kN, the double-helix system reduced geofoam displacement by approximately 51% compared with the single-helix system. Both configurations exhibited highly linear load–displacement relationships within the investigated design-load range. The numerical model reproduced the peak pull-out capacities and relative performance trends of the two anchor configurations, although it underestimated the displacement at peak resistance, particularly for the double-helix anchor. The novelty of this study lies in the systematic integration of laboratory pull-out testing and three-dimensional numerical analysis to evaluate geofoam reinforcement using helical anchors in sapric peat. The results indicate that the double-helix configuration provides more effective displacement control under the investigated uplift loading conditions and may support the design of lightweight embankments in peatland environments.]]>
