Research on the Influence of Shield Tunneling Parameters on Buildings Side-passed by Overlapping Tunnels

Objective The influence of shield tunneling parameters (upper chamber and shield tail grouting pressures) for the subsequent line of overlapping tunnels on existing buildings is analyzed to provide a reference for similar projects.

Method Based on the project of Guigu Street Station to Fanrong Road West Station section on Changchun Metro Line 5, which passes laterally alongside existing buildings, numerical simulation is employed to analyze the variation patterns of building settlement and stress distribution with changes in the upper soil chamber pressure and shield tail grouting pressure. The findings are verified against monitoring data.

Result & Conclusion  Increasing the upper soil chamber pressure can effectively reduce building settlement and inclination, and the reduction range gradually diminishes with further chamber pressure increase. Excessive upper chamber pressure induces unfavorable tensile stress in buildings. Meanwhile, increasing the shield tail grouting pressure also reduces building settlement and inclination, but the effect is less significant compared to that of the upper chamber pressure. Furthermore, the long side of the building close to the tunnel axis is most affected by excavation disturbance and should be given priority attention during actual construction.