Volume 26 Issue 1
Jan.  2026
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CAO Wei-ping, ZHANG Zuo-peng, HE Zhan-peng, LUO Long-ping, LI Qing, KONG Gang-qiang. Model tests on temperature field and heat exchange efficiency of energy pile in loess foundation[J]. Journal of Traffic and Transportation Engineering, 2026, 26(1): 224-235. doi: 10.19818/j.cnki.1671-1637.2026.097
Citation: CAO Wei-ping, ZHANG Zuo-peng, HE Zhan-peng, LUO Long-ping, LI Qing, KONG Gang-qiang. Model tests on temperature field and heat exchange efficiency of energy pile in loess foundation[J]. Journal of Traffic and Transportation Engineering, 2026, 26(1): 224-235. doi: 10.19818/j.cnki.1671-1637.2026.097
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Model tests on temperature field and heat exchange efficiency of energy pile in loess foundation

doi: 10.19818/j.cnki.1671-1637.2026.097
  • 1.

    School of Civil Engineering, Xi'an University of Architecture & Technology, Xi'an 710055, Shaanxi, China

  • 2.

    Shaanxi Key Lab of Geotechnical and Underground Space Engineering, Xi'an 710055, Shaanxi, China

  • 3.

    Xi'an Engineering Investigation and Design Research Institute of China National Nonferrous Metals Industry Co., Ltd., Xi'an 710054, Shaanxi, China

  • 4.

    School of Civil Engineering and Architecture, Xi'an University of Technology, Xi'an 710048, Shaanxi, China

  • 5.

    Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, Jiangsu, China

Funds:

National Natural Science Foundation of China 51078308

Natural Science Basic Research Program of Shaanxi Province 2024JC-YBMS-299

More Information
  • Corresponding author: CAO Wei-ping, professor, PhD, E-mail: wp_cao@163.com
  • Received Date: 2025-01-19
  • Accepted Date: 2025-11-27
  • Rev Recd Date: 2025-11-09
  • Publish Date: 2026-01-28
    Abstract
  • Model tests on energy piles in loess with different saturation degrees under summer/winter mode were conducted to understand the heat exchange efficiency characteristics. Remolded loess was used with saturation degrees of 42% and 69%, respectively. The precast reinforced concrete piles were applied as the model energy pile, with diameters of 50, 65, and 80 mm, installed with U-shaped and W-shaped heat exchangers. The energy piles were placed in the loess using two methods: embedded/static jacking. The experimental results show that the temperature field in surrounding soils exhibits obvious three-dimensional characteristics, and the heat exchange between the pile and soil is mainly in the horizontal direction. The horizontal influence zone of the energy pile temperature is not less than 3 times the pile diameter. The temperature gradient in surrounding soils is closely related to the saturation degree of loess, operating mode, soil displacement effect during construction, and heat exchanger type. Overall, the heat exchange efficiency in summer mode is lower than that in winter mode. A higher saturation degree for loess corresponds to a higher heat exchange efficiency in summer mode, while the truth is the opposite in winter mode. Either in the winter or summer mode, when the loess saturation degree is the same, the heat exchange efficiency of embedded piles with W-shaped heat exchanger in loess is higher than that of jacked piles with U-shaped heat exchanger, while the heat exchange efficiency of embedded piles with U-shaped heat exchanger is the lowest. The heat exchange efficiency of energy piles with diameters of 50 and 65 mm is nearly the same, while that of 80 mm diameter ones is much lower. Compared with non-displacement piles, the displacement piles can improve the heat exchange efficiency by around 13.7% averagely.

     

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