Centrifuge Modelling of Displacement Piles and Installation Effects-Paper

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The paper demonstrates how centrifuge modelling can reproduce displacement-pile installation while measuring both pile and ground responses. Such experiments help address the difficulty of capturing installation-induced soil deformation and changes in soil properties through analytical or numerical methods alone.<br /><br />In the University of Western Australia centrifuge, 45 model piles were installed in consolidated kaolin clay; 21 were jacked in-flight at 40g. The piles were pushed at a constant rate, with installation resistance and pore pressures recorded. T-bar penetrometer tests measured soil strength before and after installation. The model used a low pile-shaft replacement ratio of approximately 1.4%, representative of some pile-supported embankments.<br /><br />Installation generated excess pore pressures, but measurements showed no noticeable increase in pile installation resistance. T-bar tests conducted after the pore pressures had dissipated for 14 hours at 40g likewise showed no evident increase in undrained shear strength. For the tested soil conditions and pile arrangement, the findings support the common design assumption that displacement-pile installation does not increase the surrounding soil’s strength.<br /><br />The study concludes that centrifuge testing can provide valuable experimental data on pile installation effects. Its ability to combine in-flight installation with load and pore-pressure monitoring and pre- and post-installation soil testing offers a useful means to improve understanding of displacement-pile behaviour and inform foundation design.

Keywords

centrifuge modelling

displacement piles

pile installation

kaolin clay

pore pressure

undrained shear strength

T-bar penetrometer

soil deformation

pile installation resistance

foundation design