Bearing behavior of monopile-friction wheel hybrid foundation under combined horizontal-torsional loads in sand soil

Abstract

The monopile-friction wheel hybrid foundation withstands various loads in the marine environment, such as the vertical load (V) transmitted from the superstructure, horizontal loads (H) caused by wind or wave, torsional loads (T) caused by rotating structures. In this article, 1 g model tests are used to investigate the behavior of the monopile-friction wheel hybrid foundation under independent horizontal load (H) or torsional load (T), and combined loads (H-T) in sand soil, respectively. The failure envelopes of H-T loading plane are obtained from the measured load–displacement data with the simplified calculation equations presented as well. Finally, we also discuss quantitatively the influences of the pre-vertical loads, foundation geometry and loading eccentricity on the bearing capacity of the hybrid foundation via the three-dimensional finite element method. The results indicate that the displacement response of the hybrid foundation under independent loading is significantly different from that subjected to combined loads (H-T). The torsional bearing capacity of the hybrid foundation can be significantly improved by 6.6–33.34% under pre-horizontal load. The horizontal bearing capacity of the hybrid foundation decreases sharply after the pre-torsional load reaches a certain value, which decreases by about 20%. The presence of a friction wheel improves the torsional/bending moment distribution of pile shaft.

Keywords:

• Monopile-friction wheel hybrid foundation
• combined loading
• bearing capacity
• model test
• failure envelopes
• numerical analysis

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Authors’ contributions

Xinjun Zou: conceptualization, writing-review and editing, funding acquisition, supervision; Taotao Wei: writing-original draft, methodology, derivation, visualization, formal analysis; Zijiang Yang: writing-review and editing.

Data availability

All data and models generated or used in this study are available from the corresponding author by request.

Additional information

Funding

The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (Grant No. 52178329).