Abstract:

The horizontal ground settlement characteristics and longitudinal settlement characteristics of monitoring point of Donggelu StationBinhulu Station shield tunnel on Nanning Metro Line No. 3 bored by slurry balance shield and EPB shield are analyzed by field monitoring data. The software FLAC3D is used to simplify the simulation of the two shield construction methods, and the monitoring results are used to verify the feasibility of the simulation method. Three working conditions, tunnels bored by slurry balance shield and EPB shield respectively, tunnels bored by slurry balance shield and those bored by EPB shield, are designed and simulated, and corresponding ground deformation characteristics are studied. The study results show that: (1) When the tunnels are bored by slurry balance shield and EPB shield respectively, the ground settlement curve is biased towards the side of the tunnel bored by EPB shield; when the tunnels are bored by slurry/EPB shield, the closer the ground to the tunnel, more obvious the "W"shape of the settlement curve presents. (2) When the tunnels are bored by EPB shield, the ground settlement is large, and the influencing range of surface settlement is about 50 m; however, when the tunnels are bored by slurry balance shield, the ground settlement is relevant small, and the influencing range of surface settlement is about 30 m. (3) The horizontal surface displacement is the largest when the tunnels are bored by EPB shield.

Key words: doubletrack metro tunnel, EPB shield, slurry balance shield, ground deformation, field monitoring, numerical simulation