Numerical Study on Lateral Response of Offshore Monopile in Sand under Local Scouring Conditions

Currently, p-y models have been broadly adopted for estimating the lateral bearing capacity of large-diameter monopiles in offshore engineering. However, the existing p-y curves cannot reflect the effect of pile diameter D on the lateral response of monopiles under local scouring conditions. In order to extend the existing p-y model to a large-diameter pile, a well-calibrated three-dimensional pile-soil model performed by ABAQUS is used to study the effect of the pile diameter D on the ultimate soil resistance P and the initial stiffness k of the Lin’s p-y model. Based on the numerical simulation results, two diameter-related parameters A and B, which represent the relationships between the ultimate soil resistance and the initial stiffness obtained by the numerical model and the Lin’s p-y model, respectively, are proposed and introduced into the Lin’s p-y model to present a modified p-y model. The comparison results show that the proposed modified p-y model is capable of providing a better estimation of the lateral response of large-diameter monopiles than the existing p-y model under a scouring condition.