为研究挤压地层双护盾隧道掘进机（TBM）作用下围岩变形及应力场特征，采用FLAC3D建立了完整模型，并详细阐述了隧道掘进机（TBM）施工过程中的模拟方法，重点分析了隧洞纵横断面内围岩位移场、应力场、塑性区特征。模拟结果表明，两腰下部范围内的围岩与TBM护盾发生接触并产生挤压，拱顶并未接触；受刀盘与护盾连接处的尺寸高差和前后护盾的锥度影响导致仰拱围岩内出现3次加卸载，仰拱内部环向应力和径向应力均大于拱顶和两腰，而且其主应力方向与径向线斜交，受扰动剧烈，但仰拱下方70°范围内的围岩基本处于弹性状态；横向断面内围岩塑性区自上而下逐渐减小，且距掌子面越远塑性区范围越大，但后盾塑性区范围变化不大。

A complete 3D numerical simulation by using FLAC3D is developed to investigate the features of surrounding rock deformation and stress field in squeezing ground excavation by double shield tunnel boring machine(TBM). The TBM model was based on the real geometry and the nonuniform gap between the shield and the ground. A great emphasis is placed on the key steps to simulate TBM tunneling in accordance with the practical construction. In this paper, we mainly studied the characteristics of displacement field, stress field and the plastic zone on the cross section and the longitudinal section profile of the tunnel. The results obtained in numerical modeling indicate that the surrounding rock which located in the lower part of the wall is contact to the shield of TBM, whereas the crown is not. Three loading and unloading phenomena are observed in the surrounding rock of floor, which can be attributed to the impact of the geometry of size difference on the cutter head and shield and the conicity of the front shield and the rear shield. Moreover, the circumferential stress and the radial stress in floor is greater than the crown; and the wall and the orientation of major principal stress is severely perturbed and obliquely crossing the radial of the tunnel. But the ground on the lower part of 70° is in elasticity. The plastic zone outside the front shield gradually decreases from top to bottom on transverse section and increases with the greater distance away from the excavation face. But, it has no obvious change in ground outside the rear shield.