Bearing capacity and soil deformation around modified suction caisson in clay under monotonic horizontal loading

Abstract

Suction caissons for offshore wind turbine (OWT) are required to withstand larger horizontal load resulting from wind and wave. In order to increase the horizontal bearing capacity, the modified suction caisson (MSC) was proposed. Experimental studies were conducted to investigate the bearing behavior and soil deformation around MSC in clay under horizontal loading. Influence factors such as the undrained shear strength and installation methods were studied. Results show that the horizontal bearing capacity of the MSC increases by 20–40% compared with the regular suction caisson (RSC). The horizontal bearing capacity of the MSC increases with increasing the undrained shear strength. In addition, the horizontal bearing capacity of the MSC installed by jacked force is higher than that installed by applied suction. The rotation center was found to move downwards with the increase of the suction caisson deflection. In the limit state, upward deformation of clay and cracks within the deformed clay were observed in the loading direction. However, a gap between clay and the suction caisson edge opposite the loading direction was found. The deformation range around the MSC is larger than that around the RSC, indicating that the MSC can mobilize more soil to resist the horizontal load.

Keywords:

• Modified suction caisson (MSC)
• horizontal bearing capacity
• undrained shear strength of clay
• rotation center
• clay deformation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research is supported by the Natural Science Foundation of China (Grant Nos. 51879044), Natural Science Foundation of Shandong Province (Grant No. ZR2019BEE007), and Open Research Fund of Hunan Provincial Key Laboratory of Key Technology on Hydropower Development (Grant No. PKLHD202006).