Influencing Factors and Technical Support Measures for the Construction of Shield Tunnels Underneath the Existing Subway Lines with Small Spacing

The shield tunneling under the existing subway line adopts the earth pressure balance shield method. In the silty clay layer, the tunneling parameters of the shield tunnel are optimized, namely, soil pressure,thrust, cutter head torque, cutter head speed, tunneling speed, synchronous grouting the volume, simultaneous grouting pressure, unearthed volume and shield attitude, etc. reduce the impact on the existing operating lines,which has a good guiding significance in the field of shield construction of the Xi'an Metro.