SUCTION CAISSON ANCHOR AND DYNAMICALLY INSTALLED FISH ANCHOR IN CALCAREOUS SILT

Suction caisson anchors are proven reliable anchoring solutions for tethering floating facilities in shallow to deep water. Dynamically installed anchors have been identified as the most cost-effective option for particularly deep water developments. Recently, the dynamically installed fish anchor has been introduced, adopting a geometry taken from nature. Physics for installing these two anchors are different. However, owing to the counterbalancing effects of strain rate dependency and strain softening the operative undrained shear strength around these two anchors may be similar. After the completion of installation, for suction caisson anchors, the skirt is embedded in the seabed with a soil plug inside and the lid sits on or slightly above the mudline, and for dynamically installed anchors, the whole body is mostly fully embedded into the ground. Furthermore, under operational loadings, the fish anchor is found to dive (penetrate deeper) in the seabed deposit. These different embedment conditions and potential diving for the fish anchor cause differences in the behaviour and mobilised capacity under operational monotonic and cyclic loadings in calcareous silt.