Monitoring and simulation of the thermal behavior of cast-in-place pile group foundations in permafrost regions

• Published in: Cold regions science and technology 2022-04, Vol.196, p.103486, Article 103486
• Main Authors: Hou, Xin, Chen, Ji, Yang, Bin, Wang, Jinchang, Dong, Tianchun, Rui, Pengfei, Mei, Qihang
• Format: Article
• Language: English
• Subjects: Cast-in-place pile foundations; Freezeback process; Permafrost; Pile group; Thermal disturbance annuli
• ISSN: 0165-232X; 1872-7441
• DOI: 10.1016/j.coldregions.2022.103486

The heat emitted in the construction process of cast-in-place (CIP) pile foundations and the subsequent cement hydration process cause a thermal disturbance in the surrounding permafrost and reduce the early load capacity. In this paper, based on monitoring and simulation, the thermal behavior of CIP pile groups in permafrost regions was analyzed. The results indicate that the overlapping thermal disturbance annuli of CIP pile foundations increased the freezeback time. With increasing overlap, the freezeback time increases. Compared to warm permafrost regions, pile foundations in low-temperature permafrost regions experience a larger thermal disturbance range, and the resultant thermal disturbance annuli are more likely to overlap, which can increase the freezing time. Large-diameter pile foundations in warm permafrost regions exhibit a larger thermal disturbance range because more hydration heat is generated, and the thermal disturbance annuli more likely overlap. The freezeback time notably increases, while the permafrost around the pile foundation has not fully recovered after ten years. •The thermal characteristics of the group pile foundations in permafrost were studied in combination with numerical simulation and field tests.•The overlapping thermal disturbance annuli of CIP pile foundations increase the freezeback time.•Pile foundations in low-temperature permafrost regions experience a larger thermal disturbance range, and thermal disturbance annuli are more likely to overlap.•Large-diameter pile foundations exhibit a larger thermal disturbance range, and the freezeback time increases significantly after the thermal disturbance annuli overlap.