Abstract The importance of accurate prediction of limiting cavity depths during offshore spudcan foundations installation has been variously highlighted in the literature. Nonetheless, most of the previous research is deterministic in nature and confined to homogenous soils. Since offshore clayey soils can be highly spatially variable, there is a practical need to take proper account of the spatial variability in the prediction of limiting cavity depths. In a bid to remedy this situation, large deformation finite element calculations combined with three-dimensional random fields were repeatedly conducted in this study within a Monte-Carlo framework. The continuous penetration of a spudcan initiated from surface was explicitly modeled until a full-localized flow-around mechanism was observed. Spatial variability was found to clearly affect the soil back-flow and thereby the limiting cavity depth, the latter of which takes a range of values that can be approximately modeled as a log-normal distribution. Characteristic limiting cavity depths at various probability levels were ascertained. An algebraic expression was proposed to explicitly predict the characteristic limiting cavity depths in random soils from the fractile. Particular attention was paid to the lower and upper 5% characteristic values, which are likely to be useful for reliability-based design.

中文翻译：

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确定空间变化海床中离岸桩基的极限空洞深度

摘要 在海上桩板基础安装过程中准确预测极限空腔深度的重要性在文献中得到了不同程度的强调。尽管如此，以前的大多数研究本质上都是确定性的，并且仅限于均质土壤。由于近海黏土在空间上的变化很大，因此在预测极限空洞深度时需要适当考虑空间可变性。为了弥补这种情况，本研究在蒙特卡罗框架内反复进行了结合三维随机场的大变形有限元计算。从表面开始的桩钻的连续穿透被明确地建模，直到观察到完全局部化的流动机制。发现空间可变性明显影响土壤回流，从而影响极限空洞深度，后者取一系列值，可以近似建模为对数正态分布。确定了不同概率水平下的特征极限空腔深度。提出了一种代数表达式，以从分形中明确预测随机土壤中的特征极限空腔深度。特别注意了下限和上限 5% 的特征值，它们可能对基于可靠性的设计有用。提出了一种代数表达式，以从分形中明确预测随机土壤中的特征极限空腔深度。特别注意了下限和上限 5% 的特征值，它们可能对基于可靠性的设计有用。提出了一种代数表达式，以从分形中明确预测随机土壤中的特征极限空腔深度。特别注意了下限和上限 5% 的特征值，它们可能对基于可靠性的设计有用。