Abstract:

Taking the construction of the shield tunnel crossing railway bridge of Wuhan Metro Line 3 as an example, the displacement of the beam structure, track line and pile bridges under different burial depths (2D, 2.5D, 3D) are analyzed with the finite element software ANSYS and then being validated with the field data to study the effect of tunnel buried depth on the settlement deformation and horizontal displacement of existing bridges during the process of shield tunnels passing through adjacent railway bridges. The results showed that: (1) Increasing the depth of tunnel will increase the vertical displacement of pile foundation, beam and rail structure, and when the depth of the tunnel is 18 m, the maximum settlement of the pier exceeds the limit value; (2) When the tunnel burial depths are 12 m, 15 m and 18 m, the deformations of piers and beam structures are mainly vertical displacements, while horizontal displacements are smaller; (3) When the surface subsidence limit is met, the deformation of the upper bridges, rails, and other structures caused by the tunnel excavation is controlled by appropriately reducing the tunnel burial depth.

Key words: shield tunnel, passing below bridge, buried depth, numerical simulation, displacement