Progressive failure of helical anchors in sand under monotonic uplift loading

Helical anchors have been widely used by the onshore industry and are now being considered as anchors for offshore renewable energy infrastructure. As a step towards better understanding of helical anchor behaviour, this paper presents an investigation of the deformation mechanisms observed in centrifuge model tests of a single plate subjected to drained monotonic uplift loading in sand. The particle image velocimetry/digital image correlation technique was used to provide visualisation of soil movements leading to the identification of strain fields around the anchor model for different sand relative densities and plate embedment ratios. Two mechanisms were identified, which govern the volume change and particle displacement in the vicinity of the anchor during uplift.