Abstract:

On basis of the problems met in shield boring of the smallradius curve section of the first stage R413 project on line 9 of Shanghai Metro, the author mainly studies on shield machine and segment selection, backfilling grouting behind the segments, temporary longitudinal strengthening rib, segment bolt retightening, offsetting of shield boring axis in advance, measurement and attitude control of shield machine, shield boring parameter selection, ground loss and secondary grouting, boring direction correcting, control of the gap between the segment and tail skin, by means of numerical simulation and literature research. Furthermore, the author provides some detailed measures on construction and design. The author also provides solutions for such problems as blocking of shield machine, break of extrados of segments under tail skin and edge breaking of segments under tail skin occurring after the shield machine reaches the transition curve. These measures ensure the successful and safe construction of smallradius shieldbored tunnel. This paper can provide references for similar projects in the future.

Key words:  shield, curve with small radius, construction technology