Effects of Monopile Installation on Subsequent Lateral Response in Sand. II: Lateral Loading

Monopiles under in-service conditions are subjected to lateral forces and resultant bending moments from the offshore environment. The subsequent lateral response following installation is significantly influenced by the initial soil state postinstallation, which is influenced by the pile installation process, as demonstrated in previous numerical studies. To date, there are no technical guidelines established for considering the installation effects on the design of laterally loaded monopiles. This paper is the second of a pair of companion papers that investigate the effect of different installation methods on the subsequent response of monopiles under lateral loading. The paper focuses on the quantification of the effect of pile installation on the initial stiffness and lateral capacity. The numerical model is first validated against purpose-designed centrifuge tests. The analysis confirms that impact driven piles have significantly higher initial stiffness and lateral capacity than jacked piles and wished-in-place piles. The effect of installation methods on the lateral response is also influenced by the initial soil density, driving distance, pile geometry, stress level, and load eccentricity. The study highlights the importance of considering the effects of the installation process on the subsequent lateral pile response.