Hydro-mechanical modelling of interaction between monopiles and cross-anisotropic sandy seabed subjected to wave loadings

ABSTRACT

Cross-anisotropy is a typical feature of marine sediments. To explore the monopile-seabed interaction in cross-anisotropic sandy seabed subjected to wave loadings, a hydro-mechanical model is established and the nonlinear monopile-soil contact behaviours such as slip and separation are considered. It is shown that, when the seabed properties in the horizontal plane were kept constant, the increase of seabed anisotropy results in three effects: A) the decrease of vertical coefficient of permeability k_V, B) the increase in vertical elastic modulus E_V and shear modulus G_V, and C) the decrease of Poisson’s ratio µ_HV. Effect A will lead to a reduction of excess pore water pressure and an aggravation of momentary liquefaction around the monopiles. Effect B is conducive to the decrease of lateral displacement and bending moment of the monopiles. Besides, wave-induced settlement of the monopiles is observed and is found to be alleviated by effect B.

KEYWORDS:

• monopile
• cross-anisotropy
• wave loading
• liquefaction
• nonlinear contact

Acknowledgments

The authors are grateful for the financial support from the National Natural Science Foundation of China (Grant No. 41727802 and No. 51679134).

CRediT authorship contribution statement

Dagui Tong: Conceptualisation, Methodology, Validation, Formal analysis, Writing – Original Draft. Chencong Liao: Methodology, Writing – Review & Editing. Jinjian Chen: Writing – Review & Editing, Supervision, Funding acquisition.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [51679134, 41727802]