3D numerical simulation for mechanical influence of multi-line tunneling on existing tunnel in soft clay

The increase of underground infrastructure implies a need to make rational and efficient use of underground space. Therefore, new tunnels have to be constructed more often in close proximity to the existing tunnel and the multi-line tunneling cases are usually encountered in situ. The deformation of the existing tunnel in soft clay during the construction is studied with the 3D finite element numerical simulation method. In order to simulate the shield obliquely crossing the existing tunnel, thin-layer elements are employed in the 3D finite element model. Furthermore, the complex tunneling procedure is fully considered. 3D simulation for lining installation and grouting process has been realized. Finally, the results from present approach are compared with the measured data, good agreement is obtained. It may provide certain basis to draw up correctly protective measurements of metro tunnels influenced by adjacent excavation.