Study on the influence of structural spacing on the deformation caused by the excavation of shield underpass socket pipe gallery

In a prefabricated composite pipe gallery with socket joints, the repeated loading and unloading effect of shield construction on the overlying soil and the existing pipe gallery may cause considerable deformations to the pipe gallery at the joint while ensuring its own bearing capacity. The shield tunnelling underneath the existing pipe gallery project of the Fuzhou Metro was used as a basis to model the socket pipe gallery on ABAQUS finite element software. The influence of changes in the pipe-tunnel spacing on the deformation and displacement of the pipe gallery and stratum were investigated. It was found that when the shield passes through the pipe gallery with 0.25 times the tunnel diameter, in addition to the settlement area of the disturbance centre, uplift areas are created on both sides of the pipe gallery and the surface. Meanwhile, because of the socket structure of the pipe gallery, the vertical displacement of the pipe gallery is not synchronized with the settlement of the lower soil. Furthermore, with the increase in the pipe-tunnel spacing, the settlement trough of the vertical displacement curve of the pipe gallery and the stratum are gradually broadened, and the peak settlement gradually increases.