Abstract Piles used for jacket type foundation of offshore wind turbine are subjected to highly cyclic tension and compressive loading. The pile capacity under cyclic tension loading decreases with increased number of loading cycles due to reduction of the pile shaft resistance. A numerical simulation scheme is presented, which allows the calculation of the pile capacity degradation (CDM) due to cyclic loading for driven steel piles. The volume compaction of soil near the pile surface during the cyclic loading is determined from the cyclic simple shear test results and then applied to the pile-soil system. From the limited number of tests available, interaction diagrams have been developed, which give the number of load cycles leading to failure dependent on the mean load and the amplitude of the cyclic load portion, which are both related to the static pile capacity. However, such diagrams cannot account for different soil conditions or pile geometry and pile stiffness. The calculation results for different piles in sandy soil under cyclic axial loading are presented and compared with existing interaction diagrams. Finally, recommendations regarding further investigations and improvements of the method are given.

中文翻译：

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循环轴向荷载作用下桩的承载力退化方法

摘要 海上风力发电机导管架式基础桩承受高循环拉压载荷。由于桩轴阻力的降低，循环拉伸载荷下的桩承载力随着加载循环次数的增加而降低。提出了一种数值模拟方案，该方案允许计算由于打入钢桩的循环载荷引起的桩容量退化 (CDM)。循环加载过程中桩表面附近土壤的体积压实由循环简单剪切试验结果确定，然后应用于桩土系统。从可用的有限数量的测试中，已经开发出相互作用图，它给出了导致失效的载荷循环数，取决于平均载荷和循环载荷部分的幅度，这两者都与静桩容量有关。然而，这样的图表不能说明不同的土壤条件或桩几何形状和桩刚度。给出了循环轴向荷载作用下沙土中不同桩的计算结果，并与现有的相互作用图进行了比较。最后，对方法的进一步研究和改进提出了建议。