In view of the basically synchronous implementation of the newly excavated channel and the shield tunnel,the key excavation area of the channel above the shield tunnel is studied,and the key control distance along the transverse area of the shield tunnel is given according to the ultimate equilibrium theory of the Tershaki foundation soil,the distance between the top of the shield tunnel and the bottom of the channel foundation pit,the diameter of the shield tunnel and the internal friction angle of the soil.Due to the rheological characteristics of soft clay,the excavation process above the shield tunnel is numerically simulated on the basis of soft-soil creep(SSC)model and Plaxis finite element software,and the characteristics of soil deformation at the bottom of the foundation pit and the top of the shield tunnel are analyzed.The stress release time required for the soil deformation stability is analyzed for typical projects.The results show that after soil is excavated,the uplift deformation of the soil at the bottom of the foundation pit and the top of the shield tunnel continue to increase with the extension of time until the deformation rate becomes stable.The soil stress is gradually released in 45 d after the typical engineering excavation is completed.The results can provide security for the shield tunnel to be crossed in the future.