Abstract

It is necessary to understand the response of monopile foundations for large offshore wind turbines (OWTs) with rated powers of $6-9 MW$ under cyclic loading. For this purpose, a monopile model test study was conducted in saturated medium dense sand under long-term unidirectional lateral sinusoidal cyclic loading for $12,000$ cycles. The model pile was constructed with displacement transducers on the pile head and strain gauges along the pile length. The experimentally obtained bending moment, displacement, soil reaction evaluation along the pile length, pile head displacement accumulation, and lateral soil-pile stiffness were substantially different from the results of the American Petroleum Institute (API)-recommended method of determination and were significantly affected by the number of loading cycles. The experimentally based soil reaction $(p)$-pile displacement $(y)$ curves obtained considering the maximum soil reactions for particular cycles were compared with the $p$-$y$ curves recommended by the API. The maximum soil reaction $(p)$ during the increase in pile displacement $\left(y\right)$ obtained experimentally was significantly higher than the soil reaction obtained with the API method. The p–y curves obtained experimentally show similarities with those determined with the API method at only small pile displacements in the initial stage of the curves.

摘要

有必要了解额定功率为$\mathrm{6个}-9 米W$在循环加载下。为此，在长期单向横向正弦循环荷载下，在饱和中密砂中进行了单桩模型试验研究。$12,000$周期。模型桩在桩头上装有位移传感器，沿桩长装有应变计。实验得到的弯矩、位移、沿桩长的土体反应评价、桩头位移累积、侧向土桩刚度与美国石油学会（API）推荐的测定方法结果有很大差异，受到显着影响按加载循环次数。基于实验的土壤反应$(p)$-桩位移$(是)$将考虑特定循环的最大土壤反应获得的曲线与$p$-$是$API推荐的曲线。最大土壤反应$(p)$在桩位移增加期间$\left(是\right)$实验获得的显着高于用 API 方法获得的土壤反应。实验获得的 p-y 曲线与 API 方法在曲线初始阶段仅发生小桩位移时确定的曲线相似。