Research on Stability in Metro Tunnel Constructing with Shallow Buried Covered Excavation in Loose Sand Layers

For subway tunneling in urban underground, high safty of construction is needed.However, the safty and rationality of excavating plan are forecasted difficultly because of consealment. Based on the Zhang-Shen tunnel construction of Shenyang subway, bench method, single side-wall heading excavation method and CD excavation method are numerical simulated; according to the numerical calculation results and the constructing process, bench method is adopted; the ground settlement caused by excavation monitored during excavating is in the allowed range and the tunnel is safe during excavating.