Small-Scale Modelling of Thermomechanical Behavior of Reinforced Concrete Energy Piles in Soil

Rui Zhao, Anthony Kwan Leung, Davide Vitali, Jonathan Adam Knappett, Zheng Zhou

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Small-scale physical model tests have been increasingly used to study the thermomechanical soil-pile interaction, but existing model piles are highly simplified and do not have representative thermal properties or the quasi-brittle mechanical behavior of reinforced concrete (RC). This study aims to overcome these shortcomings by presenting a new type of model RC. This consists of a mortar (plaster, sand and water) with copper powder added to tune the mixture’s thermal properties, along with a steel reinforcing cage. Fine sand was used to represent geometrical scaling of the prototype aggregates to correctly capture quasi-brittle structural response. Adding copper powder content of 6% (by volume) matched the coefficient of thermal expansion and thermal conductivity of prototype concrete, without changing the axial and flexural properties of model piles. In 1-g soil-structure interaction tests, the model pile was able to serve as an effective heat exchanger for transferring heat from a water-carrying pipe embedded within the mortar to the surrounding soil. The model RC exhibited cyclic pile head settlement due to repeated pile heating/cooling.
Original languageEnglish
Article number04020011
Number of pages10
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number4
Early online date13 Feb 2020
Publication statusPublished - Apr 2020


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