Abstract
Pile geothermal heat exchanger (PGHE) has attracted great interests in recent years, but some new challenges have emerged with its application, especially in understanding its thermo-mechanical behaviors. In this paper, based on the experimental data from a modified direct shear test, a finite element simulation model is developed to investigate the thermo-mechanical behavior of PGHE. The simulation model has been verified by an in-suit test. The influence of interface behavior, thermal loads, and soil properties on the PGHE's thermo-mechanical behavior has been investigated. The results show that the changes in contact force and friction coefficient has to be considered in a comprehensive way in estimating the influence of thermal load on the bearing capacity of PGHE. Compared with the results without thermal loads, bearing capacity of PGHE shows a decreasing ratio of 8.7%, and an increasing ratio of heating is found to be 13.2%. In addition, the simulation results suggest that without head load imposed, at a certain depth, the axial stress has a linear relationship with the change of temperature, but when a head load is imposed, the linear relationship is only separately valid in each temperature region (heating or cooling). The thermo-mechanical performance of PGHE should be fully considered during the design stage, and this paper has the certain actual reference significance to engineering applications.
Original language | English |
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Pages (from-to) | 356-366 |
Number of pages | 11 |
Journal | Applied Thermal Engineering |
Volume | 139 |
DOIs | |
Publication status | Published - 5 Jul 2018 |
Keywords
- Energy pile
- Ground-coupled heat pump
- Pile geothermal heat exchanger
- Thermo-mechanical performance
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Industrial and Manufacturing Engineering