Study on p-y curves of monopile in layered soil based on field test

A field test on lateral monotonic loading is conducted on a monopile (D=2 m) for offshore wind turbines in layered soil in Jiangsu province. The bending moment and the deformation of the monopile shaft are measured. The results show that the maximum bending moment is below the ground level and approximately equal to 3 times diameter of monoplie, and the zero of bending moment and the zero of deformation move to deeper gradually/correspondingly as the loading increasing. By deducing shallow soil reaction against depth of monopile based on the measured results, which indicates that soil reaction is influenced by the depth of soil layer and m values in layered soil. Combined m method and hyperbolic p-y curves method, the initial stiffness of p-y curves in layered soil are studied, and the influence of soil m values, the effect range of spring, the embedded depth and diameter are considered by the modified equation. The comparison of lateral load-displacement at pile head calculated by several soil reaction methods show that m method only catch small lateral deflection with limited linear elastic deformation; API p-y curves method is too conservative; hyperbolic p-y curves method is non conservative; the proposed p-y curves method can well match with the measured results. © 2019, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.