Full-scale in-situ tests on energy piles: Head and base-restraining effects on the structural behaviour of three energy piles

Sütman, Melis; Brettmann, Tracy; Olgun, C. Güney

doi:10.1016/j.gete.2018.08.002

Cited by 75 publications

(14 citation statements)

References 14 publications

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“…The distribution of stresses and strains induced by imposed thermal loads highly depends on the degree of freedom of the pile (DOF). It goes from maximum strains ( ,-.// = −α 23 ∆T) for completely free piles (DOF = 1) to maximum internal stresses ( ,-45/6 = E 23 α 23 ∆T) for perfectly restrained piles (DOF = 0) [3,113]. Therefore, Soga and Rui [60] suggested considering the maximum thermal-induced displacement of a free pile ( ,-.// = −α 23 ∆TL) and the maximum thermal-induced stress ( ,-45/6 ) of a fully restrained pile as the primary design criteria to assess the serviceability and safety of the system.…”

Section: Mechanical Criteriamentioning

confidence: 99%

A review on energy piles design, evaluation, and optimization

Mohamad

Fardoun

Meftah

2021

Journal of Cleaner Production

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Section: Mechanical Criteriamentioning

confidence: 99%

A review on energy piles design, evaluation, and optimization

Mohamad

Fardoun

Meftah

2021

Journal of Cleaner Production

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“…Hence, compared with BHE, an energy pile can provide a higher heat transfer capacity [6,7]. Moreover, in the past few decades, considerable efforts have been focused on energy piles through full-scale tests [3,8], model tests [9,10] and numerical modeling [11,12].…”

Section: Introductionmentioning

confidence: 99%

A Finite Element Model for Investigating Unsteady-State Temperature Distribution and Thermomechanical Behavior of Underground Energy Piles

Zhao

et al. 2022

Applied Sciences

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The underground energy geostructure represented by the energy pile is one of the key paths for the cooperative development of underground space and geothermal energy. Because of its advantages of low cost, high efficiency and no extra occupation of underground space, it has become a feasible alternative to the borehole heat exchanger. The change in the temperature field of the energy pile and its surrounding ground not only affects the geological environment but also influences the thermomechanical performance and the durability of the structure. However, the temporal and spatial unsteady-state temperature distribution of piles and surrounding rock under typical intermittent and unbalanced thermal load conditions is still unclear. In this paper, a finite element model was applied to analyze the unsteady-state temperature distribution, and the thermomechanical behavior of the energy pile group was developed and verified. The temperature field distribution of pile and surrounding rock under typical intermittent working and unbalanced thermal load conditions were determined. Moreover, the thermomechanical behavior characteristics of the energy pile group were investigated. Finally, the influences of pile layout on the thermomechanical behavior of the energy pile group were identified by designing six different scenarios. The results indicate that under typical intermittent operation conditions, the temperature of the energy pile and surrounding ground near the heat exchange pipe varies periodically. For areas with unbalanced cooling and heating loads, long-term operation of energy piles leads to thermal accumulation, and the maximum temperature of energy piles occurs in the first daily cycle. In summer/winter working conditions, the increase/decrease in pile temperature induces axial compression/tensile stress. When the pile group is partially used as the energy pile, the non-energy pile acts as the “anchor pile”, and it generates the added tensile stress.

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“…Through indoor model tests, Yang et al [33,34] found that the thermal cycle of the energy pile will increase the temperature rise of the pile and soil and cause the pile body temperature to rise and the pile body stress and top displacement to accumulate. In addition, numerous studies have revealed that the deformation and stress distribution of the energy pile during temperature cycling are affected by the restraint at the end of the pile [35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Simulation and Analysis of the Thermal-Mechanical Response of an Energy Pile

Zhang

Liu

et al. 2022

Lithosphere

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An energy pile undertakes the functions of supporting the superstructure and controlling the indoor temperature of the building, and the thermal-mechanical coupling response of an energy pile makes its load transfer mechanism different from that of conventional engineering piles. Moreover, the thermal-mechanical coupling responses of the energy piles in summer and winter conditions are also different and need to be explored separately. Based on a ground source heat pump pile foundation workshop project in Kunshan city, Jiangsu Province, a multiphysics simulation study was carried out. The simulation results of the outlet water temperature and pile settlement are consistent with the real-world measurements, which verifies the reliability of the numerical simulation. The responses of the temperature distribution, axial stress, lateral shear stress, and settlement of the energy pile in summer and winter were analyzed, and the response laws of the energy pile in different seasons were obtained. Compared with the pure conventional load state, under the effect of thermal-mechanical coupling in winter conditions, the maximum compressive stress of the pile body is reduced by about 11.5%, but the settlement of the pile top increases by about 47.66%. Therefore, the winter conditions should be used as the design energy for the normal use of the pile. The control condition of the limit state: compared with the pure conventional load state, the maximum compressive stress of the pile increases by about 12% and the settlement of the pile top decreases by about 7.23% under the thermal-mechanical coupling effect of the summer condition. Therefore, the summer condition is the pile control conditions for the limit state of the body’s carrying capacity.

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Full-scale in-situ tests on energy piles: Head and base-restraining effects on the structural behaviour of three energy piles

Cited by 75 publications

References 14 publications

A review on energy piles design, evaluation, and optimization

A review on energy piles design, evaluation, and optimization

A Finite Element Model for Investigating Unsteady-State Temperature Distribution and Thermomechanical Behavior of Underground Energy Piles

Simulation and Analysis of the Thermal-Mechanical Response of an Energy Pile

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