Contrast Analysis on Deformation Characteristic of Urban Subway Tunnel Excavation by Numerical Simulation and Field Measurement

Under the particular geological conditions of clay and sandy soil interbed, through numerical analysis and field monitoring, the surface settlement, horizontal deformation and the stress distribution were analyzed after the tunnel excavation in a metro station in Beijing, China. There are differences of surface deformation whether the backfill grouting behind arch during tunnel excavation. While the backfill grouting behind arch, the ground surface settlement and the horizontal displacement reach 9.36 mm and 2.16 mm respectively. But while no backfill grouting behind arch, the ground surface settlement and the horizontal displacement are 14.51 mm and 8.85 mm respectively. The maximum ground settlement induced by tunnel excavation is directly proportional to ground loss ratio. When the ground loss ratio is 1%, the result is well consistent with the field measurement value and the numerical simulation result.