Long-term thermo-mechanical behaviour of energy piles in clay. Issue 4 (15th April 2019)

• Record Type: Journal Article
• Authors: Nguyen, Van Tri; Wu, Nanwangzi; Gan, Yixiang; Pereira, Jean-Michel; Tang, Anh Minh
• Is Part Of: Environmental geotechnics. Volume 7:Issue 4(2020)
• Page Start: 237
• Page End: 248
• Publication Date: 2019-04-15
• Subjects: energy geotechnics -- piles & piling -- numerical methods; Geotechnical engineering -- Periodicals; 624.15
• DOI: 10.1680/jenge.17.00106
• Languages: English
• ISSNs: 2051-803X

Abstract

Abstract : In engineering practice, energy pile foundations are often designed for the lifetime of the building. Thermal exchange between a pile and the surrounding soil depends on the annual energy needs of the building, as heating mode in winter and cooling mode in summer. Thus, energy pile foundations will undergo a heating–cooling cycle per year. In the present work, an experimental method based on a small-scale pile model installed in saturated clay was used to study the thermo-mechanical behaviour of energy piles under thermal cycles. Thirty cycles were applied (to represent a 30-year period if the daily cycles are neglected) while a constant pile head load was maintained. Four tests were performed corresponding to pile head loads equal to 0, 20, 40 and 60% of pile resistance. The results obtained show an increase in irreversible pile head settlement with the thermal cycles. In order to interpret the experimental results better, the finite-element method is used to simulate the experiments numerically. This allows the important role of pile thermal contraction/expansion in the pile–soil interaction under thermo-mechanical loading to be highlighted.