Anchor chain is often used to connect floating structure to anchor in seabed. For taut or semitaut mooring line in sand seabed, part of the chain is embedded in the sand, and the interaction between chain and the sand is of significance for the configuration and tension of mooring line. It is known that tangential shear behavior affects the tension transfer. However, there are few experimental studies about the tangential shear behavior between chain and sands. In this paper, a series of tests were conducted to study the effect of shear speed, confining stress, chain nominal diameter(db) and sand particle size on the tangential shear behavior. It is found that the tangential resistance basically conforms to the bi-linear relationship. The increase of confining stress promotes tangential resistance as well as the displacement to fully mobilize the resistance. Regardless of nominal diameter, the tangential resistance is fully mobilized within 1db displacement. The effective width of all tests distributes in a range from 8.91 to 11.94. This work can provide the parameters for numerical study and engineering design (API-RP2SK, ISO 19901-7 and DNV-RP-E301).
Shengjie Rui, Zhen Guo, Lizhong Wang, Wenjie Zhou and Kanmin Shen
Keywords: anchor chain, sands, tangential shear behavior, effective width
Publisher: DFI