Original scientific paper
https://doi.org/10.21278/brod74206
Motion characteristics of vertically loaded anchor during drag embedment in layered clay
Bin Wang
; Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province, Hangzhou 311122, China Powerchina Huadong Engineering Corporation Limited, Hangzhou 311122, China
Yuqi Jiao
; State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China
Dongsheng Qiao
; State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China
Shan Gao
; Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province, Hangzhou 311122, China Powerchina Huadong Engineering Corporation Limited, Hangzhou 311122, China
Tianfei Li
; Powerchina Huadong Engineering Corporation Limited, Hangzhou 311122, China
Jinping Ou
; State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China
Abstract
As a widely used taut-wire mooring system for deepwater platforms, the Vertically Loaded Anchor (VLA) has better performance in bearing capacity, angle adaptability, and deepwater installation than other systems. However, the installation process of the VLA and its motion characteristics are significantly impacted by multi-layered seabed soil. In this paper, the coupled Eulerian‒Lagrangian (CEL) large deformation finite element analysis method has been applied to analyse the continuous penetration of a VLA in nonuniform clay with an interbedded stiff layer. A detailed parametric study has been carried out to explore the trajectory, drag angle, movement direction and drag force of the VLA in layered clay with different embedded depths, thicknesses and undrained shear strength of the stiff layer. The CEL numerical analysis results have been validated by comparison with the analytical solutions from the inverse catenary equation. Excellent agreement has been obtained between the results from the CEL analyses and the analytical solutions. The stiff layer leads to concave and convex shapes on the trend lines of the movement direction angle and drag forces, respectively. The embedded depth of the stiff layer determines where the concave and convex shapes appear on the trend lines, while the thickness affects the sizes of the openings of the shapes. The most decisive parameter, an abrupt variation in the undrained shear strength, causes predominant rotation at the interface of layered clay. It diminishes the final embedment depth and ultimate stable drag force, meaning that the bearing capacity of the VLA severely declined in layered clay.
Keywords
vertically loaded anchor; coupled Eulerian‒Lagrangian method; layered clay; motion characteristic
Hrčak ID:
299393
URI
Publication date:
1.3.2023.
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