Abstract:

The ground is often affected by the construction of overlapping shield tunnels, as a result, it is necessary to study the mechanical behavior and deformation rules caused by the interaction in the construction of overlapping tunnels. In the paper, the rules of the deformation of surrounding ground induced by the construction of the overlapping shield tunnels on Lintong Line of Xi’an Metro, as well as the rules of the influence of the construction of the left tunnel tube on the constructed right tunnel tube, are studied. The result shows that:1) After the construction of the overlapping tunnel is completed, the ground surface settlement trough induced by the construction of the tunnels, which takes a belt shape, is distributed alone the tunnel. 2) The ground settlement increases as the degree of the vertical overlapping magnitude increases; the maximum ground surface settlement reaches 9.79 mm at the fully vertical overlapping point; 3) The influence of the construction of the left tunnel tube on the constructed right tunnel tube takes the form of lateral pushing and increasing the strata supplementary stress. At the vertically overlapping section, such influence can be ignored. The maximum horizontal displacement of the right tunnel tube induced by the construction of the left tunnel tube reaches 175 mm, and the maximum settlement of the right tunnel tube reaches 1.97 mm.

Key words: Xi’an Metro, overlapping tunnel, shield, settlement, deformation, displacement, numerical calculation