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The spatial variability of soil has long been recognised, yet there is a dearth of research on the response of piles under lateral loading that considers this variability, especially for the lateral load transfer (P-y) curve in spatially variable clay. To address this gap, the study presents a three-dimensional random finite element analysis utilising a non-stationary random field to model soil variability with a linearly increasing trend. The results reveal that the spatial variability significantly affects the lateral capacity of the pile, emphasising the importance of accounting for this variability in pile design. Additionally, the study finds that while the spatial variability affects the failure mechanism, the mechanism remains comparable to that observed in deterministic analyses. The spatial variability has a substantial effect on ultimate soil resistance pressure, which can be fitted using a normal probability distribution function. An adjust factor is suggested to calculate the characteristic value, and from this characteristic value, the fractiles of ultimate soil resistance pressure can be calculated. This study provides an evaluation method for the spatial variability effect of soil, facilitating a cost-effective design of pile foundation. • The study explores the net soil pressure, failure mechanism and lateral load transfer (P-y) curves at varing depths in spatially variable soil. • The research discusses the impact of inherent variation and autocorrelation of soil on the response of lateral loaded piles. • A framework is proposed to integrate the effects of spatial variability into the current engineering guidelines. • An illustrative example is provided to demonstrate the practical significance of the research outcomes. [ABSTRACT FROM AUTHOR]

Sand compaction piling has been long recognized to exert considerable influence on the treated soils in various aspects. One noteworthy regard is the strength set-up or the set-up effect in soil due to the sand compaction pile installation. However, due to its complex nature, it is extremely difficult to numerically model the actual piling process, which is characterised mainly by the repeated withdrawal and re-driving of the casing tube and by the gradual expansion of the sand column. Crude simplifications of various forms had thus to be adopted in the past. This paper reports the development of an innovative approach that can replicate not only the actual sand compaction pile installation process but also the post-installation soil consolidation phenomenon. With that, the set-up effect can be realistically reflected by numerical means. • We propose a novel numerical strategy to analyse the mechanical properties of sand compaction pile foundation. • The proposed innovative method can capture all the typical features during the sand compaction pile installation process. • The mechanical deformation characteristics and set-up effect of sand compaction pile foundation have been studied deeply. • A simple and convenient approach for predicting the strength growth of sand compaction pile foundation is proposed. [ABSTRACT FROM AUTHOR]

The bending moment response of straight pile foundations, as the dominant factor of spudcan-pile interaction, has received focused attention in the close joint operation between jacket platforms and jack-up drilling rigs. As the foundation for the same widely used in jacket platforms, the research on the batter pile is still a knowledge gap in this field. This paper presents a numerical study of the bending moment response of batter piles at different inclination angles and azimuthal angles during spudcan installation. Using a coupled Eulerian-Lagrangian finite element method, the effects of flexural rigidity, stiffness ratio, spudcan-pile clearance distance, and pile length on the pile head bending moment were sequentially evaluated. It was found that the pile bending moment response is related to the change in soil flow mechanism caused by spudcan penetration and becomes more significant with the increase of inclination angle; under the same inclination angle, the bending moment response is the most dangerous when the azimuthal angle is 0°. Based on the parameter study, a simple method is proposed to estimate the pile head bending moment during spudcan installation. The outcome may facilitate incorporating pile spatial inclination into spudcan-pile interaction research and contribute to related safety design. [ABSTRACT FROM AUTHOR]