Abstract:

Problems such as axis deviation, segment offset and ground surface settlement may occur to shieldbored tunnels on smallradius curves. A section of the running tunnel from Huojuguangchang station to Shijiazhuangdong station on Line 1 of Shijiazhuang Metro is located on a smallradius curve. Countermeasures in terms of shield type selection, segment type selection, boring parameters, simultaneous grouting, secondary compensation grouting and segment bolt retightening are taken for the tunnel. In the end, the deviation of the axis of the completed tunnel has been controlled within the range from -50 to +50 mm, the offset of the segments has been controlled within 10mm and the ground surface settlement has been controlled within the range from -20 to +10 mm.

Key words: tunnel on smallradius curve, shield tunneling, thrust, axis, segment offset, grouting, bolt retightening, settlement