Abstract: Shifudalu station of Shenyang Metro is constructed by small diameter tube curtain construction method. The three-dimensional model of station structure and stratum was built by using FLAC^3D. The deformation laws of stratum and the main structure caused by dynamic excavation of small diameter tube curtain were analyzed and summarized. The results show that the surface settlement caused by small diameter tube curtain excavation takes on staged characteristics. Under the influence of group hole effect and pre-support of the pipe curtain， the shape of the settlement tank changes frequently. The ground surface settlement caused by soil excavation between transverse guide tunnels accounts for 50.54% of the final settlement， which is the key stage of ground surface settlement control. After the completion of tube curtain-beam-pile-column construction， the deformation of the main structure shows a good synergistic effect. The vertical deformation of the beam is small at both ends of the station and large in the middle. The horizontal displacement of the side pile and the middle column increased significantly during the negative second storey construction period， and accounts for 47.1% and 55.8% of the maximum horizontal displacement respectively. This stage is the key stage in controlling the deformation of the main structure.

Key words: small diameter tube curtain method; subway station; numerical analysis; surface settlement; structure deformation