This paper mainly investigates the effect of soil spatial variability on failure mechanisms and capacities of strip foundations under uniaxial loading on marine clay deposits with linearly increasing undrained shear strength using random finite element analysis. The soil spatially variable feature is characterised by a non-stationary random field where the ratio of the standard deviation and mean of undrained shear strength is maintained. The effect of soil parameters, including the dimensionless soil heterogeneity index, the coefficient of variation of shear strength and the dimensionless autocorrelation distance, on the uniaxial capacities are discussed. In addition, shapes of failure envelopes for combined loading in the probabilistic analysis are compared to those shapes in deterministic analysis. Results demonstrate that the difference in shapes of failure envelopes between deterministic and probabilistic cases is minimal and can be neglected for practical purposes. Probabilistic uniaxial capacities derived in this study can be employed to scale probabilistic failure envelopes, which represent sizes of probabilistic failure envelopes. The obtained results offer insights into how soil spatial variability can be comprehensively considered in the design of an offshore shallow foundation.

本文主要通过随机有限元分析研究了土壤空间变异性对不排水抗剪强度呈线性增加的海相粘土沉积物在单轴加载下条形地基破坏机制和承载力的影响。土壤空间可变特征的特征是非平稳随机场，其中保持不排水抗剪强度的标准偏差和平均值的比值。讨论了无量纲土壤非均质性指数、抗剪强度变异系数和无量纲自相关距离等土参数对单轴承载力的影响。此外，将概率分析中组合载荷的失效包络形状与确定性分析中的形状进行比较。结果表明，确定性和概率性情况之间的故障包络形状差异很小，在实际应用中可以忽略不计。本研究中导出的概率单轴容量可用于缩放概率故障包络，它代表概率故障包络的大小。获得的结果为如何在近海浅层基础设计中综合考虑土壤空间变异性提供了见解。