Centrifuge modelling of the performance of suction anchor in soft clay

Abstract

Suction anchors are large cylindrical anchors and well-suited for both catenary and taut mooring systems. The determination of horizontal and vertical load components hinges upon factors such as inclined loading angle and the padeye position, significantly influencing its failure mechanism. This study undertook a series of geotechnical centrifuge tests to scrutinize the behavior of suction anchor under lateral loading. Precise measurements were taken for variables including the pore pressure at the anchor tip, soil pressure along the anchor, anchor capacity, as well as the displacement and rotation around X, Y, and Z axes. The anchor failure mechanisms and interaction coefficients within a dissipation function were determined from the experimental results. The failure angle β serves as an indicator of anchor rotation in the translational failure mechanism, and αr describes anchor rotation in backward and forward movements. Under the inclined loading angle (θm) of 35°, the anchor failed in translational mechanism, with its ultimate bearing capacity surpassing that of the anchor failing through backward and forward mechanisms. Upon elevating the padeye location moved upward to 4L/7 to 2L/3, the anchor failed in a forward mechanism, accompanied by a significant decrease in soil pressure in the passive side. This separation of the soil plug from the anchor, driven by accumulated displacement and rotation, resulted in 25% decrease in ultimate bearing capacity. Conversely, when the inclined loading reduced from 35° to 20° at padeye location, the anchor failed in a backward mechanism, with no observed separation of the soil plug from the anchor.