Numerical advancements on the analysis of dynamically installed anchors

• Published in: Ocean engineering Vol. 182; pp. 343 - 359
• Main Authors: Zhao, Yanbing, Kim, Youngho, Hossain, Muhammad Shazzad, Nazem, Majid, Liu, Jun, Hu, Yuxia
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.06.2019
• Subjects: Clays; Dynamic installation; Dynamically installed anchors; Numerical modelling methods; Offshore engineering; Pullout; Clays; Numerical modelling methods; Offshore engineering; Dynamic installation; Pullout; Dynamically installed anchors
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2019.04.079

Challenges associated with dynamically installed anchors (DIAs) include prediction of anchor embedment depth and subsequent pullout performance under chain loading. Numerical analyses on the behaviour of DIAs require advanced modelling methods that can deal with a) hydrodynamic aspects during the free-fall in water; b) large soil deformations with high strain rate effects during the dynamic penetration; c) post-installation consolidation; d) pullout performances considering installation and anchor chain effect. This paper divides the behaviour of DIAs into three stages, including anchor free-fall in water (Stage 1), anchor dynamic penetration in soil (Stage 2), and anchor pullout under operational loadings (Stage 3), and gives an overview of numerical advancements on the analysis of DIAs at each stage. By illustrating typical numerical results and comparisons between various methods, the advantages and limitations of the numerical modelling methods are highlighted. The advantage of the finite volume method (FVM) based on computational fluid dynamics is its capability in the full simulation of an anchor dynamic installation in water followed by in soil (Stages 1 and 2). However, the stress-induced anisotropy of the soil cannot be captured by the FVM. The finite element (FE) method, especially the large deformation finite element (LDFE) method, is preferable to analyse Stages 2 and 3. The effects of soil properties on the performance of DIAs can be quantified by the LDFE method, in terms of strain rate, strain softening, pore pressure and drag force. •Review of numerical modelling methods and soil constitutive models.•Dynamically installed anchors.•Dynamic installation in water.•Dynamic installation and loading in clay.•Comparative advantages and limitations of numerical modelling methods.