Capacity of spudcan foundations in clay under sustained uplift

• Published in: Applied ocean research 2024-07, Vol.148, p.104035, Article 104035
• Main Authors: Zhen, Wang, Jiang Tao, Yi, Shi Jie, Xu, Fei, Liu, Shuai, Yin, Yu Tao, Pan
• Format: Article
• Language: English
• Subjects: Centrifuge test; Clays; Consolidation; Finite element simulation; Spudcan extraction; Sustained capacity
• ISSN: 0141-1187; 1879-1549
• DOI: 10.1016/j.apor.2024.104035

•We use centrifuge experiments and large deformation finite element simulations to investigate the capacity of vertically loaded spudcan foundations under sustained uplift.•The sustained threshold load of spudcans ranges from about 50 % to 70 % of their monotonic capacity.•The monotonic capacity after vertical sustained loading is investigated.•A step-by-step guide is provided to estimate the sustained capacity of spudcans for various operational durations. Spudcan extraction has long been a challenging issue in engineering, necessitating a thorough understanding of spudcan sustained capacity. Prior studies have predominantly focused on the monotonic capacity of spudcans, which is distinct from the engineering practice of sustained loading. This paper studies the capacity of spudcans deeply embedded in normally consolidated clay during and after vertical sustained loading through centrifuge tests and numerical simulations. The sustained threshold load of spudcans ranges from approximately 50 % to 70 % of their monotonic capacity, and it gradually decreases with increasing operation period. When the applied load exceeds the threshold load, the uplift displacement of the spudcan exhibits creep characteristics characterised by an initial rapid rate, followed by consistent growth and ultimately accelerated failure. The greater the sustained load is, the sooner the spudcan fails. When the sustained load is far lower than the threshold load, the undrained spudcan capacity after sustained loading closely aligns with the monotonic undrained capacity under long-term operation consolidation. However, this capacity diminishes considerably at sustained forces near the threshold load. A step-by-step guide is also included to estimate the sustained threshold load for various operational durations.