Parameters Analysis and Monitoring of Shield Undercrossing Existing Tunnel

Soil warehouse pressure, synchronous grouting pressure and volume, shield thrust and advance speed of shield tunnel undercrossing existing tunnels were summarized. Existing tunnels deformation was analyzed. Conclusions are as follows. Firstly, soil warehouse pressure, synchronous grouting pressure and volume are main factors affecting existing tunnel deformation and control parameters for shield crossing. Secondly, soil warehouse pressure should be 1.5 to 1.8 times of static earth pressure and a little smaller than passive earth pressure. Thirdly, synchronous grouting pressure should be controlled in the range of formation pressure value and grouting volume should be 1.5 to 1.8 times of shield end clearance. Finally, advance speed should be in a low and uniform state.