Research on Deformation Law of Different Layers during Metro Tunnel Construction Undercrossing the Existing Urban Road in Upper-soft and Lower-hard Ground

Large surface settlement is often caused when there are tunnels constructing in the upper-soft lower-hard ground. Taking the antuo-mountain entrance/exit lines of Shenzhen subway line 7,which pass under the North ring Road, as an example, the essay combines numerical simulation with field monitoring to make researches. Based on the utilization of monitoring measurement, the essay analyses the surrounding rock and s stratum deformation law during the tunnel pass under the existed road. The result shows: The loading on road surface has significant impact on settlement of tunnel surrounding rocks. When the distance between twin tunnels is relatively small, the full-section grouting method obviously influenced the deformation of shallow strata above the grouting interval, and so is the deeper part near the tunnel. Full-section grouting method has positive effect on surface settlement controlling, while it is important to concern the upheaval. In this project, the full-section grouting method impact harder on the