Abstract:

The shield machine came across existing bridge piles while boring from Shayong station to Shayuan station of the Guangzhou～Foshan line of Guangzhou Metro. It was of great importance to ensure the structural safety of the tunnel and the safety and normal function of the bridge. The following countermeasures were adopted to deal with the existing bridge piles: 1) The tunnel section was excavated by the mining method; 2) The reserved bedrock underneath the existing bridge piles was reinforced from inside the mined tunnel; the existing bridge piles were then properly connected to the secondary lining of the mined tunnel before the piles inside the tunnel were cut off; 3) The shield machine went through the mined tunnel and the segments were erected. The analysis on the monitoring data demonstrated that the countermeasures used here were feasible and rational. This paper provides reference for similar projects in the future. 

Key words: Guangzhou Metro, shieldbored tunnel, existing bridge, pile foundation, secondary lining, pile cutting, emergency counterplan, monitoring