This paper studies the p-y curve for monopile in clay under cyclic lateral loading. The stressstrain responses of the clay samples bored from Bohai Sea, China are investigated through static and cyclic simple shear tests. FE analyses are then performed to examine the applicability of the direct correlation method, which constructs the p-y curves for monopiles by scaling from soil stress-strain responses. Based on the experimental results, the design formulas that correlate the static p-y curve with stress-strain curve from simple shear test are proved to be applicable for the clay samples from Bohai Sea. The contour diagram in terms of cyclic shear strain is established so that the cyclic p-y curve can be scaled from the stressstrain curve corresponding to a specific equivalent number of cycles, N/sub eq/. Lastly, beam-column analyses are performed for different distributions of N/sub eq/ along the pile. The results indicate that simplifying the distribution of N/sub eq/ as a constant value equal to that at pile head will overestimate the pile head displacement and maximum bending moment by less than 10%. Therefore, the cyclic accumulation procedure may only be required at pile head for the convenience of design.
Yuan Zhou, Jingbin Zheng, Dong Wang and Hailei Kou
Keywords: cyclic loading, offshore wind turbine, p-y curve, monopile, clay
Publisher: DFI