Pile groups under axial loading: an appraisal of simplified non-linear prediction models

Abstract

The settlement behaviour of vertically-loaded pile groups has been the subject of an extensive body of research over the past two decades. In particular, this work has identified the overconservatism associated with predictions of pile interaction derived from elastic theory and the corresponding amplification of group settlement relative to single pile values. Researchers have since redoubled efforts to refine settlement predictions for pile groups towards more economical design, largely through more rigorous treatment of soil stiffness nonlinearity. Although foundation design engineers are increasingly employing three-dimensional continuum analyses to quantify pile interaction on a site−specific basis, simplified design approaches remain an integral part of preliminary foundation design. The purpose of this paper is to undertake a critical examination of these methods with a view to increasing their potential for take-up by foundation engineering practitioners. A database of simplified models has been collated for the prediction of nonlinear pile interaction that exists within vertically-loaded pile groups. These models are categorised as either analytical or empirical. The development, limitations, and range of applicability of these models are explored in detail in the context of some published case histories.

Large-scale model tests of a single pile and two-pile groups for an offshore platform in sand

“…This can result in additional soil strains and, for instance, in the displacement of the interlocked soil block in between the piles. To cope with these issues, simplified models based on linear elasticity (Randolph and Wroth 1979), empirical and analytical methods (Randolph, 2003;Sheil et al 2019), and advanced numerical solutions (Jardine and Potts, 1988;Clancy and Randolph 1993;Han et al 2019) have been developed since the 1970s but find scarce application in practice where simplistic methods are often employed (Tomlinson and Woodward 2015). Experimental evidence from large-scale test setups could decrease the uncertainty associated with some of the advanced analysis methods and, in turn, increase the confidence in using appropriate analysis tools.…”

Condition Diagnosis of Long-Span Bridge Pile Foundations Based on the Spatial Correlation of High-Density Strain Measurement Points

“…In addition to the mechanical behavior of pile foundation structures under scouring and earthquakes, many scholars have conducted targeted research on the special stress mode of pile foundations. The deformation of pile foundations under vertical loading, lateral loading, and inclined loading has been studied [20][21][22][23][24]. The method for predicting the deformation of pile foundations has been widely studied [25][26][27], and a numerical model with greater load conditions and a wider range has been further developed [28][29][30][31][32].…”

Optimization Method of Reducing the Differential Settlements of Piled Raft Foundations Based on Pile‐to‐Pile Interaction Theory

“…e interaction factor method (IFM) [23,24] is used for accounting PPI in the design of pile groups. Interaction factor α ij [25,26] for pile i due to pile j, corresponding to the spacing between piles i and j, is given as follows:…”