Investigation of thermo-mechanical response of a geothermal pile through a small-scale physical modelling

Hashemi Senejani, H ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1051/e3sconf/202020505016
  3. Publisher: EDP Sciences , 2020
  4. Abstract:
  5. Energy piles have been used around the world to harvest geothermal energy to heat and cool residential and commercial buildings. In order to design energy geo-structures, thermo-mechanical response of the geothermal pile must be carefully understood. In this paper, a small scale physical model is designed and a series of heating thermal cycles with various vertical mechanical loads are performed. The instrumented pile is installed inside a dry sand bed. Changes in pile head displacement, shaft strains and pile and sand temperatures are monitored using an LVDT, strain gauges and thermocouples, respectively. Prolonged heating cycles, which would continue until boundary temperature changes, would allow the investigation of excessive heat injection when service loads are active on the pile. The thermal response is discussed including confirmation of a temperature influence zone around the pile, the increase in soil temperature, and minimum vertical heat dispersion in the soil. The mechanical response includes plastic settlements when the vertical load passes 20% of ultimate capacity. Plastic settlements have been observed at the half of the capacity reported for the shorter thermal cycles in similar models. The decrease in the capacity indicates a reduction in elastic response of the soil during longer thermal cycles. © The Authors, published by EDP Sciences, 2020
  6. Keywords:
  7. Geothermal energy ; Office buildings ; Soils ; Strain ; Structural design ; Structural geology ; Thermal cycling ; Thermocouples ; Boundary temperature ; Commercial building ; Mechanical response ; Physical modelling ; Plastic settlements ; Temperature influence ; Thermo-mechanical response ; Ultimate capacity ; Piles
  8. Source: 2nd International Conference on Energy Geotechnics, ICEGT 2020, 20 September 2020 through 23 September 2020 ; Volume 205 , 2020
  9. URL: https://www.e3s-conferences.org/articles/e3sconf/abs/2020/65/e3sconf_icegt2020_05016/e3sconf_icegt2020_05016.html