The base shear and moment may play important roles in behaviors of offshore monopiles, and traditional p-y curves cannot model the base forces. In this study, a new semi-analytical model for monopile is proposed, from which base forces and displacements can all be obtained simultaneously. Green's functions for poro-visco-elastic soil and Timoshenko beam are used. Full bond between pile and soil is assumed, which means the results are suitable for the normal operating conditions for offshore wind turbines. Selected numerical results are examined for different pile lengths, pile thickness, load eccentricity, soil parameters and frequencies of excitation. These results show the values of base forces are notable only when the pile's aspect ratio is very small. Besides, an interesting phenomenon is found: Ignoring the base effects will only lead to a negligible influence on pile impedances and responses, even when the pile's aspect ratio is very small. The reason is that the pile shaft near the base in the “no base effect” model will take the stresses the base bears in the “with base effect” model. The pile's overall responses and impedances are not sensitive to the detailed stress distributions around the pile base in this elasto-dynamic problem.

基础剪力和弯矩在海上单桩和传统py桩的行为中可能起重要作用曲线无法对基本力进行建模。在这项研究中，提出了一种新的单桩半解析模型，从该模型可以同时获得基本力和位移。格林函数用于多孔黏弹性土和Timoshenko梁。假定桩与土壤之间完全粘结，这意味着结果适合海上风力涡轮机的正常运行条件。针对不同的桩长，桩厚，荷载偏心率，土壤参数和激励频率，检查了选定的数值结果。这些结果表明，仅当桩的纵横比非常小时，基础力的值才有意义。此外，还发现了一个有趣的现象：忽略基本影响只会对桩的阻抗和响应产生微不足道的影响，即使桩 的长宽比非常小。原因是在“无基础效应”模型中靠近桩基的桩身将承受“有基础效应”模型中基体承受的应力。在这种弹力问题中，桩的整体响应和阻抗对桩基周围的详细应力分布不敏感。