In the construction of an F‐type cross‐passage in an overlapping‐type shield tunnel using the artificial ground freezing method, the development of the distal frozen wall is difficult to control, and ground deformation is influenced by the superimposed disturbance of successive construction steps. Existing studies are insufficient to fully characterize the evolution of the frozen temperature field and frozen displacement field. To address this, the F‐type cross‐passage between Lingbi Road Station and Yaoyuan Road Station of Hefei Metro Line 8 adopted measures such as installing inclined freeze pipes for reinforcement and applying time‐sequence construction to control the distal cooling capacity and ground displacement field. Numerical simulation combined with analysis of field test data was conducted to investigate the evolution laws of the frozen temperature field and frozen displacement field in this F‐type cross‐passage. The results indicate that by installing long inclined freeze pipes on both sides of the main frozen reinforcement zone, the minimum thickness of the frozen wall at the control section ( X = −12.03 m) reached 2.51 m after 55 days of active freezing, satisfying the design requirements. At the same time, after 55 days of ground freezing, the soil temperature in the central region of the Y = 0 m section ranged from 2.5°C to −2.5°C. This indicates that the soil was at the critical freezing temperature, which is favorable for the underground excavation of the F‐type cross‐passage. Regarding ground deformation, during both the freezing reinforcement and excavation stages, a pancake‐shaped heave/settlement zone appeared on the surface above the cross‐passage, with slight shifts in its center position. The surface displacement field generally showed a decreasing or increasing trend outward from this central position.
Li et al. (Thu,) studied this question.