Objective  Metro shield construction in soft soil areas inevitably disturbs surrounding soil mass, threatening the safety of surrounding buildings and structures in severe cases. To control stratum deformation effectively, it is necessary to study the ground settlement characteristics and influencing factors caused by metro shield tunnel construction.

Method Relying on a section project of Tianjin Metro Line 7, finite element calculation models for both a single tunnel and twin tunnels are established to analyze the effects of influencing factors, including stratum loss rate, tunnel face pressure, burial depth, and tunnel spacing on ground settlement.

Result & Conclusion When the burial depth is twice the tunnel diameter, stratum loss rate and tunnel face pressure significantly affect the maximum ground settlement, but have a weaker impact on ground settlement range. Tunnel burial depth significantly impacts both ground settlement amount and its range. When the burial depth is twice the tunnel diameter, insufficient tunnel face pressure causes significant settlement, while excessive tunnel face pressure causes obvious ground heave. With increasing twin tunnel spacing, the ground settlement trough transitions gradually from V-shaped to U-shaped, and then to W-shaped. When a W-shaped ground settlement trough is exhibited, the maximum ground settlement of the trailing tunnel exceeds that of the leading tunnel.