Abstract:
Helical anchors are widely used in geotechnical engineering owing to their ease of installation and ability to resist both tensile and compression forces. However, their pullout performance in layered soils remains an area of ongoing research. This study investigates the pullout capacity of helical anchors embedded in medium-dense to dense sand overlain by soft to firm clay. A series of model tests were conducted to assess the effects of key parameters, including embedment depth, helix size, soil layer thickness and soil shear strength. The experimental results were supplemented by a numerical study using finite element limit analysis to develop dimensionless design charts for practical applications. The findings highlight the influence of soil layering on anchor behaviour, with variations in failure mechanisms observed depending on the relative thickness and strength of the clay and sand layers. This study enhances the understanding of helical anchor performance and offers practical insights for engineers working with layered geotechnical conditions.