Session: 10-05-01: Bucket Foundations and Caissons

Submission Number: 154991

Simplified Two-Spring Winkler Model for Suction Caisson Subjected to Vertical Loads in Non-Homogeneous Clays 

Jacket foundations are commonly used to support offshore wind turbines (OWTs), and the vertical uplifting response of suction caissons is crucial for the stability of these foundations under substantial moments. Therefore, accurately characterizing this vertical uplifting response is essential. However, traditional modeling methods often rely on the complex “Winkler model,” which utilizes numerous springs, such as t-z and Q-z curves, to represent soil-foundation interactions.To address this challenge, this study introduces a novel simplified two-spring Winkler model that combines a single macro t-z curve with a Q-z curve, specifically tailored for suction caissons subjected to vertical loads in non-homogeneous clays. Importantly, this model incorporates site-specific soil stress-strain relationships and project-specific foundation geometries. We begin with finite element analyses (FEAs) to evaluate the soil reaction responses of vertically loaded caissons in homogeneous undrained clays. The FEA results reveal interrelationships among soil-caisson interactions, soil stress-strain relations, and foundation characteristics, enabling the development of a simplified two-spring Winkler model that effectively utilizes soil model parameters. Finally, the proposed model is validated against centrifuge test results, demonstrating its capability to accurately represent the uplift response of caissons while offering a more efficient alternative to traditional modeling methods, thus enhancing the design and assessment of suction caissons in practice.

Presenting Author: Hang Feng The Hong Kong Polytechnic University

Presenting Author Biography: Mr Feng is a PhD candidate from the Hong Kong Polytechnic University and has published several high-quality Journal papers in Ocean Engineering, Applied Ocean Research, and Acta Geotechnica.