Abstract:

Deformation and settlement will occur to the ground surface and surrounding buildings in shield tunneling. In the paper, the settlement of the bridge and ground surface in different phases of the construction of the shieldbored tunnel of phase 2 of Changping Line of Beijing Metro are analyzed, so as to minimize the influence of the shield tunneling on the bridge and ground surface. Conclusions drawn are as follows: 1) Differential settlement will occur to the bridge when the shield side crosses the bridge with low earth pressure; 2) Heaving deformation will still occur to the ground surface above the tunnel when the shield passes through the poor backfill layers under shallow cover with low grouting rate. As a result, rational earth pressure and appropriate grouting rate are very important for the safety of the bridge and the ground surface.

Key words: tunnel of Phase 2 of Changping Line of Beijing Metro, shield boring, side crossing, settlement monitoring