THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

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Performance of static drilled root energy piles under seasonal thermal loading: A study of monotonic heating in summer

ABSTRACT
Energy piles are subjected to the combined effects of thermal and mechanical loads, requiring high load-bearing capacity and efficient heat transfer. This study introduces the concept of energy piles into static drill rooted piles (SDRP), forming a new structure known as static drilled rooted energy piles (SDREP). Model tests were conducted under monotonic heating cycles to evaluate their performance, primarily for summer cooling applications. The results show that the temperature distribution patterns of SDREP and ordinary energy piles (OEP) are generally similar. However, SDREP exhibits lower pile temperature fluctuations and a higher temperature field in the surrounding soil. Under heating cycles, the additional thermal stresses in SDREP gradually increase with the number of cycles, and the peak stress occurs closer to the pile tip. During 20 heating cycles, the soil pressure at the pile tip of SDREP was always lower than that of OEP. The pile head displacement also showed different behavior: the pile head displacement of SDREP increased upward, with a final displacement accumulation of 0.19% D. The pile head displacement of OEP showed a significant downward displacement, with a final displacement accumulation of 0.57% D. After 20 heating cycles, the ultimate bearing capacity of SDREP increased by 10%. These findings provide insight into the thermo-mechanical behavior of SDREP and provide theoretical support for its application in energy pile engineering.
KEYWORDS
PAPER SUBMITTED: 2025-05-16
PAPER REVISED: 2025-07-23
PAPER ACCEPTED: 2025-07-24
PUBLISHED ONLINE: 2025-09-13
DOI REFERENCE: https://doi.org/10.2298/TSCI250516158C
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