Abstract Quick refreezing of the soils surrounding a pile in permafrost regions has been an widely concerned issue for infrastructure construction, since the bearing capacity would be quite small before a full back-freeze was finished. In order to accelerate the refreezing process of cast-in-place pile and improve its freezing force in permafrost, a fast- freezing system (FFS) using the method of artificial freezing was put forward. Field test of two piles with and without FFS was conducted in Beiluhe of the Qinghai-Tibet Plateau (QTP). A three-dimensional thermal-fluid coupling model was established to analyze the cooling effect of FFS under different conditions. The results show that FFS has a significant cooling effect, which can quickly freeze the pile foundation to −3 °C ~ -4 °C, effectively reducing the temperatures of the surrounding soils and increasing the cold reserves of the pile foundation. Even if the molding temperature and the size of the pile increase, it can still reduce the temperature of the pile to below the natural ground temperature. Since FFS significantly reduced the temperature of soils around the foundation and kept the foundation under a lower interface temperature and a higher freezing force for 7 months, the cooling technology can save the latency time of subsequent construction and is meaningful to solve the problem of rapid construction of cast-in-place pile in permafrost.

中文翻译：

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一种快速提高多年冻土地区现浇桩冻结力的速冻系统

摘要 多年冻土地区桩周土的快速再冻结一直是基础设施建设中广泛关注的问题，因为在完全回冻完成之前承载力很小。为加快现浇桩的再冻结过程，提高其在多年冻土中的冻结力，提出了一种采用人工冻结方法的快速冻结系统（FFS）。在青藏高原（QTP）的北麓河进行了有和没有FFS的两个桩的现场试验。建立三维热流耦合模型，分析FFS在不同条件下的冷却效果。结果表明FFS具有显着的降温效果，可将桩基快速冷冻至-3℃～-4℃，有效降低周围土壤的温度，增加桩基的保冷量。即使成型温度和桩的尺寸增加，仍然可以将桩的温度降低到自然地温以下。由于FFS显着降低了地基周围土壤的温度，使地基保持在较低的界面温度和较高的冻结力下7个月，冷却技术可以节省后续施工的潜伏时间，对解决快速施工问题具有重要意义。永久冻土层中现浇桩。