Small-scale modeling of thermomechanical behavior of reinforced concrete energy piles in soil

Journal article

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 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 the 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 1g 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 and cooling.

Authors: Zhao, R; Leung, AK; Vitali, D; Knappett, JA; Zhou, Z

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Society of Civil Engineers
• Journal: Journal of Geotechnical and Geoenvironmental Engineering
• Volume: 146
• Issue: 4
• Article number: 4020011
• Publication date: 2020-02-13
• Acceptance date: 2019-10-29
• DOI: 10.1061/(ASCE)GT.1943-5606.0002225
• EISSN: 1943-5606
• ISSN: 1090-0241
• Language: English
• Keywords: pile; geotechnical engineering; materials science; brittleness; thermal conductivity; flexural strength; thermal expansion; mortar; heat exchanger; thermomechanical analysis; composite material; geology; engineering