Artificial ground freezing has significant advantages in urban underground construction and for the reinforcement of water-rich soft clay layers. However, frost heave and thaw settlement induced by the freeze–thaw cycle (FTC) remain critical challenges that threaten engineering safety. To elucidate the coupled hydro-thermal-mechanical response mechanism of clay under radial freeze–thaw (FT) conditions, a single FTC experiment was conducted in this study. The results showed that the temperature, water, and stress distributions during radial FT exhibited a distinct circumferential gradient. During the freezing stage, driven by the temperature gradient and freezing suction, pore water migrated continuously toward the freezing pipe and froze into ice at the freezing front, resulting in the formation of a high-ice-content zone and significant volumetric expansion near the pipe. Upon complete freezing, the frost-heaving force increased to 34.69 kPa, corresponding to a maximum heave displacement of approximately 4.85 mm. During the thawing stage, the melting of ice caused localized pore structure collapse, while part of the thaw water percolated radially toward the freezing pipe, forming a distinct annular settlement zone in the upper soil. This behavior was mainly attributed to localized stress concentration and instability of the soil skeleton. These findings provide practical guidance for optimizing radial freezing pipe design and reducing thaw settlement risks.
Hu et al. (Mon,) studied this question.