Centrifuge modelling of inclination of 2×2 energy pile groups subjected to non-symmetrical cyclic thermal loading

MA Qijie; ZHOU Chao

doi:10.11779/CJGE20230678

Volume 46 Issue 10

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Chinese Journal of Geotechnical Engineering > 2024 > 46(10): 2158-2168. > DOI: 10.11779/CJGE20230678

MA Qijie, ZHOU Chao. Centrifuge modelling of inclination of 2×2 energy pile groups subjected to non-symmetrical cyclic thermal loading[J]. Chinese Journal of Geotechnical Engineering, 2024, 46(10): 2158-2168. DOI: 10.11779/CJGE20230678

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Centrifuge modelling of inclination of 2×2 energy pile groups subjected to non-symmetrical cyclic thermal loading

MA Qijie^1,,
ZHOU Chao^2, ,

1.
School of Energy and Power Engineering, North University of China, Taiyuan 030051, China
2.
Faculty of Construction and Environment, The Hong Kong Polytechnic University, Hong Kong 100872, China

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Received Date: July 17, 2023
Available Online: January 11, 2024

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Abstract

Abstract

During the operation of energy pile-based ground source heat pump systems, the energy piles may experience non-symmetrical temperature changes, resulting in inclination of pile group. This can affect its serviceability unfavourably. By conducting centrifuge tests, the inclination of 2×2 energy pile groups in sand induced by non-symmetrical cyclic thermal loading is quantified. During each test, 15 two-way thermal cycles with an amplitude of 10 ˚C are applied while maintaining a constant vertical load. A total of 10 tests are carried out to evaluate the effects of the distribution of energy piles within the group, magnitude of vertical load and raft-soil interaction on the inclination of pile groups. The results show that the inclination of pile group accumulates with thermal cycles at a reducing rate. Under normal vertical load (FoS = 2.0), the accumulated inclination is about 1.8‰, less than 2.5‰ as specified by the China design code. The redistribution of axial load occurs with the maximum increase of about 40% of the initial value. As the vertical load increases, the accumulated inclination can exceed 2.5‰. The inclination of pile group induced by non-symmetrical cyclic thermal loading should be well considered at the design stage.
- energy pile group,
- cyclic thermal loading,
- inclination of pile group,
- centrifuge modelling

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References

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