Penetration behaviors and pullout capacity of a novel suction anchor with inverted peripheral spikes: an experimental study

This paper presents a novel spiked suction anchor (SSA) with an outside wall incorporating inverted peripheral spikes to enhance the pullout capacity of mooring systems for offshore oil and gas platforms. Model tests were conducted to evaluate the penetration behavior and pullout capacity of the SSA in sand. Results demonstrate that the penetration resistance of the SSA to reach the target depth was not greater than that of the regular suction anchor (RSA). The measured maximum suction values and final penetration depths of the SSA were equivalent to those of the RSA, confirming its compatibility with standard suction installation procedures. Furthermore, under vertical loading, the SSA exhibited an over 11.3% increase in ultimate pullout resistance compared to the RSA. This enhancement is attributed to the inverted spikes mobilizing additional passive earth pressure and improving soil confinement during pullout. Testing under inclined loading conditions (15°, 30°, and 45°) also demonstrated superior performance. This study confirms that the SSA is a practical solution for improving pullout capacity without compromising ease of installation, which is beneficial for offshore mooring systems.