Bucket foundations have been increasingly used to support offshore wind turbines as alternatives to monopiles. Despite the substantial research effort on the bearing capacity and stiffness of such foundations in recent year, there is still a lack of knowledge regarding their cyclic response in saturated sand. In this paper, the multiaxial sand constitutive model Ta-Ger implemented in the finite deference code FLAC3D is employed in the analysis of the lateral response of bucket (skirted) foundations subjected to wind/wave loading. The model is reformulated to reproduce the cyclic response of sand for undrained, fully drained and partially drained conditions, using a unique set of calibration parameters. Having been calibrated against laboratory data available in literature, it is then used to predict the long-term cyclic lateral response of a bucket foundation in dry medium dense sand from a centrifuge experiment. After building confidence in the numerical approach the drainage effects are investigated. To gain qualitative insights into the effect of drainage conditions, the 3D numerical model, used to simulate the centrifuge test, was analyzed under saturated conditions and a range of soil permeabilities. It was shown that when flow is allowed the response up to a number-of-cycles threshold resembles that of fully drained conditions. Above this threshold, significant and abrupt increase of excess pore water pressures occurs causing liquefaction. Increasing the permeability delays the occurrence of liquefaction and the associated development of large deformations

桶形基础已越来越多地用于支撑海上风力涡轮机，以替代单桩。尽管近年来对此类地基的承载力和刚度进行了大量研究，但仍缺乏有关饱和砂土中循环响应的知识。在本文中，以有限基准代码FLAC3D实现的多轴砂本构模型Ta-Ger用于分析风荷载作用下的桶形（裙状）地基的侧向响应。使用一组独特的校准参数，可以对模型进行重新构造，以重现沙子在不排水，完全排水和部分排水条件下的循环响应。已根据文献中提供的实验室数据进行了校准，然后通过离心实验将其用于预测干燥中等密度沙子中桶形基础的长期循环侧向响应。建立起对数值方法的信心后，研究了排水效果。为了获得对排水条件影响的定性见解，在饱和条件和一定范围的土壤渗透率下，对用于模拟离心试验的3D数值模型进行了分析。结果表明，在允许流量的情况下，达到多个循环阈值的响应类似于完全排空条件的响应。超过此阈值，会出现过量的孔隙水压力显着而突然的增加，从而引起液化。渗透率的增加延迟了液化的发生以及大变形的相关发展 建立起对数值方法的信心后，研究了排水效果。为了获得对排水条件影响的定性见解，在饱和条件和一定范围的土壤渗透率下，对用于模拟离心试验的3D数值模型进行了分析。结果表明，在允许流量的情况下，达到多个循环阈值的响应类似于完全排空条件的响应。超过此阈值，会出现过量的孔隙水压力显着而突然的增加，从而引起液化。渗透率的增加延迟了液化的发生以及大变形的相关发展 建立起对数值方法的信心后，研究了排水效果。为了获得对排水条件影响的定性见解，在饱和条件和一定范围的土壤渗透率下，对用于模拟离心试验的3D数值模型进行了分析。结果表明，在允许流量的情况下，达到多个循环阈值的响应类似于完全排空条件的响应。超过此阈值，会出现过量的孔隙水压力显着而突然的增加，从而引起液化。渗透率的增加延迟了液化的发生以及大变形的相关发展 用于模拟离心机测试，在饱和条件和一定范围的土壤渗透率下进行了分析。结果表明，在允许流量的情况下，达到多个循环阈值的响应类似于完全排空条件的响应。超过此阈值，会出现过量的孔隙水压力显着而突然的增加，从而引起液化。渗透率的增加延迟了液化的发生以及大变形的相关发展 用于模拟离心机测试，在饱和条件和一定范围的土壤渗透率下进行了分析。结果表明，在允许流量的情况下，达到多个循环阈值的响应类似于完全排空条件的响应。超过此阈值，会出现过量的孔隙水压力显着而突然的增加，从而引起液化。渗透率的增加延迟了液化的发生以及大变形的相关发展