Issues with centrifuge modelling of energy piles in soft clays

This study focuses on an experimental evaluation of issues encountered when using a geotechnical centrifuge to evaluate the heat transfer, pore water pressure generation, volume change, and subsequent soil-structure interaction phenomena associated with energy pile operation in normally-consolidated Kaolinite clay. Although the scaled zones of influence of heat transfer and volume change due to thermal consolidation in centrifuge models may be wider than those expected in a field-scale prototype, centrifuge modelling results can still be used to validate numerical simulations performed at model scale. Further, topics such as the impact of temperature changes on the ultimate capacity of energy piles are well-suited to centrifuge testing due to the difficulty of performing such tests in the field. The energy pile investigated in this study is an aluminium cylinder whose temperature is controlled using an embedded electrical resistance heater. This paper focuses on an evaluation of the transient response of a soft clay layer during heating and cooling of the energy pile, an evaluation of the change in undrained shear strength profiles measured using a T-bar, and a comparison of the pullout capacity of the heated energy pile with that of an unheated energy pile.