Soil-structure interaction framework for monopiles in sand under cyclic loading

PhD student

Olgu Orakci

Supervisors

A/Prof Shiaohuey Chow	Prof Yinghui Tian	A/Prof George Anoyatis (KU Leuven)	A/Prof Stijn Francois (KU Leuven)

Project Start Date: June 2022

Project Details

Recent developments in the offshore renewable energy sector have resulted in bigger wind turbines and thus an increase in the most used monopile foundation’s diameter to guarantee their performance, especially under higher lateral cyclic loads due to waves and wind. Considering the effects of cyclic loading, especially on the long-term foundations’ capacity highlights the monopiles’ ability to control the response as well as the life span of such energy infrastructure. Despite the diverse group of available approaches to estimate cyclic soil-structure response, an alternative that can consider strain accumulation by means of a thermodynamically consistent, multi-surface plasticity framework to generate more accurate predictions of cyclic long-term displacements, remains still unexplored. A material model needs to capture experimental observations while following fundamental thermodynamic principles to ensure a realistic and physically meaningful constitutive relation.

In this regard, this joint KU Leuven (KUL) - University of Melbourne (UoM) project aims to develop a novel three-dimensional (3D) soil-structure interaction model for monopiles subjected to lateral cyclic loading in sand by means of a finite element solution using advanced soil constitutive modeling and laboratory testing. Theoretical development will include model calibration via a laboratory cyclic testing program and application to monopile-soil interaction problems including comparisons with predictions from existing models and available test data. The outcomes of the project will be integrated into an accessible design tool to enable better predictability of monopiles cyclic capacity in engineering practice.