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

Frontiers in Earth Science

Yunhu Shang¹  Jianhong Fang²  Libo Wu³  Fujun Niu⁴ 

[1] Da Xing’anling Observation and Research Station of Frozen-Ground Engineering and Environment, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Jiagedaqi, China;Qinghai Research Institute of Transportation, Xining, China;School of Civil Engineering and Hydraulic Engineering, Ningxia University, Yinchuan, China;State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China;

关键词: tangential frost-heave forces;    cast-in-place pile foundation;    thermal regime;    permafrost region;    frost heaving;    frost jacking;   

DOI  :  10.3389/feart.2022.821305

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown