The application of the artificial ground freezing method for the construction of crossadits is a complex mechanical and thermal process of the tunnel structures and the freezing ground. A 3D numerical simulation model is established using FLAC3D in this paper to study the response of the tunnel lining and the surrounding ground during the freezing and excavation. By this model, the main tunnel lining, the freezing pipes and the crossadit excavation are simulated and the mechanical responses of the tunnel and the ground are investigated. By integrating the phase change of the frozen/unfrozen soil and the soil frost action into this thermalmechanical analysis, the preliminary results of the soil heave displacements, the soil heave pressures and the lining stresses during the freezing and excavation process have been obtained, which are useful for the construction design.