Numerical study on the behaviour of horizontal anchor using upgraded SANISAND-MS

Horizontal plate anchors are widely used to secure tension leg platforms via mooring lines. A thorough understanding of the monotonic, cyclic and post-cyclic behaviour of plate anchors is essential to accurately estimate plate anchors' capacity. This paper presents a systematic investigation of horizontal rectangular plate anchors subjected to vertical monotonic and cyclic loads in quartz sand under drained conditions using three-dimensional finite-element simulations. The upgraded SANISAND-MS model is employed to accurately capture sand's ratcheting behaviour. The monotonic uplift load is affected by the contact types used between the soil-anchor interface, and it increases with increasing embedded depth ratio, aspect ratio, and relative density. The results of cyclic tests reveal that in loose and dense sands, the cyclic amplitude ratio and cyclic asymmetric ratio affect the displacement accumulation at the cyclic stage. The cyclic loading leads to a higher post-cyclic uplift load than the monotonic tests. Moreover, the post-cyclic uplift load increases more in tests with a high cyclic amplitude ratio. Investigation on local soil responses shows that this can be attributed to sand's densification, which increases sand's strength and stiffness. The study also supports the development of long term analysis for anchoring systems subjected to cyclic loading in offshore applications.