Frost Jacking Characteristics of Transmission Tower Pile Foundations with and without Thermosyphons in Permafrost Regions of Qinghai–Tibet Plateau

Yalong, Zhou; Wang, Xu; Niu, Fujun; He, Fei; Guo, Chunxiang; Liu, Deren; Jiang, Daijun

doi:10.1061/(asce)cr.1943-5495.0000246

Cited by 13 publications

(2 citation statements)

References 19 publications

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“…Considering the heat conduction of the soil skeleton and water, along with the frozen soil phase change, the differential equation of heat conduction in the soil is as follows [ 26 , 27 ]:

where T is the soil temperature (°C), ρ is the soil density (kg·m −3 ), λ is the thermal conductivity of soil (W·m −1 ·°C −1 ), C is the specific heat capacity of the soil (J·kg −1 ·°C −1 ), and t is the time (s).…”

Section: Heat Transfer Model Of the Subgrade With L-shaped Tpctsmentioning

confidence: 99%

Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions

et al. 2022

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This study focused on the coupling heat transfer mechanism and the cooling efficiency of L-shaped two-phase closed thermosyphons (L-shaped TPCTs) in the wide subgrade of permafrost regions. Considering the fact that time–space dynamics change the effects of the air temperature, wind speed, and geotemperature, a coupled air temperature–L-shaped TPCT–subgrade soil heat transfer model was established using the ANSYS 15.0 software platform, and the rationality of the model was verified through measured data. The heat-transfer characteristics of the L-shaped TPCTs and the long-term thermal stability of the subgrade were studied under different inclination angles of the evaporator (α = 15°, 30°, 50°, 70°, and 90°). Then, the cooling effectiveness of a composite subgrade with TPCTs and an XPS insulation board was numerically calculated. The results show that the heat flux of the L-shaped TPCT was the greatest when α = 50°, and the heat flux reached the maximum value of 165.7 W·m−2 in January. The L-shaped TPCT had a relatively good cooling effect on the subgrade as a whole when α = 50° and 70°, but the thawing depth at the center of the subgrade with L-shaped TPCTs reached 9.0 m below the ground surface in the 30th year. The composite subgrade with L-shaped TPCTs/vertical TPCT/XPS insulation board is an effective method to protect the permafrost foundation and improve the long-term thermal stability of the wide subgrade. The maximum heat flux of evaporation section of the L-shaped TPCT is 18.8% higher than that of the vertical TPCT during the working period of the TPCTs of the composite subgrade.

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“…Considering the heat conduction of the soil skeleton and water, along with the frozen soil phase change, the differential equation of heat conduction in the soil is as follows [ 26 , 27 ]:

Section: Heat Transfer Model Of the Subgrade With L-shaped Tpctsmentioning

confidence: 99%

Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions

et al. 2022

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“…Jiang et al (2014) determined that two-phase closed thermosyphons can significantly restrain the frost jacking of pile foundation. Zhou et al (2021) numerically researched the frost jacking behavior of pile foundations with and without twophase closed thermosyphons in permafrost regions. Few studies have reported the TFF of cast-in-place pile foundation, particularly in permafrost regions.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Thermal Regime and Frost Jacking of Pile Foundation During Operation Period in Permafrost Regions

Shang

Niu

Fang³

et al. 2022

Front. Earth Sci.

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The stability of a cast-in-place pile foundation in permafrost region is primarily subject to the thermal regime and tangential frost-heave forces (TFF) during the operation period. However, studies focusing on the thermal and mechanical characteristics of pile foundation during runtime are rare. To investigate the effect of pile foundation on the thermal regime and quantify the magnitude of unit tangential frost-heave forces (UTFF), a field experiment was conducted on the Qinghai–Tibet Plateau, China. Results showed that the cast-in-place pile foundation enhanced the heat exchange between the atmosphere and soil, which expanded the annual range of the surrounding ground temperature. Furthermore, the permafrost table depth was increased by 0.4–0.7 m (0.33–0.58 times the pile diameter). The TFF increased significantly when the soil temperature decreased from 0 to −0.5°C. Meanwhile, the thickness of the frost heaving layer was approximately double that of the active layer, in which the maximum UTFF was higher than 52.04 kPa. The adfreezing bond force of permafrost to pile shaft burdened most of the applied load, and the end bearing contributed relatively little. Findings from this study will benefit the stability maintenance and structure design of pile foundation in permafrost regions.

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Thermal performance of cast-in-place piles with artificial ground freezing in permafrost regions

Wang,

Chen,

et al. 2024

J. Mt. Sci.

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Frost Jacking Characteristics of Transmission Tower Pile Foundations with and without Thermosyphons in Permafrost Regions of Qinghai–Tibet Plateau

Cited by 13 publications

References 19 publications

Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions

Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions

Experimental Study on Thermal Regime and Frost Jacking of Pile Foundation During Operation Period in Permafrost Regions

Thermal performance of cast-in-place piles with artificial ground freezing in permafrost regions

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