Abstract: A case study is conducted on the severe shield uplift of the Nanchang Metro Line 7 in composite strata of gravel soil and argillaceous rock. To address the failure of deviation correction during shield tunneling, an emergency coordinated control method termed “rotary excavation of pilot-hole for rock-breaking and dynamic optimization of tunneling parameters” is proposed and implemented. This approach involves removing the rock intruding into the tunnel through rotary excavation of pilot holes, thereby improving the tunneling conditions from a geological perspective. By integrating dynamic adjustment of tunneling parameters, an integrated emergency solution combining geological intervention and process control is achieved. Field monitoring and numerical simulation results demonstrate the following: (1) Pilot-hole rock breaking technology effectively stops the trend of shield attitude deviation, with correction rates for shield attitude and segment deviation reaching 11.13 and 8.7 mm per ring, respectively, enabling acceptable surface settlement. (2) Maintaining the cutterhead speed of no lower than 2.2 r/min facilitates mucking and tunneling under geological conditions of this project. The mucking volume can serve as an important auxiliary indicator reflecting the tunneling state and signaling attitude fluctuations. The proposed technology is a special emergency measure characterized by high economic costs and complex procedures, applicable only to specific scenarios where conventional methods have failed.

Key words: shield uplift, composite strata, pilot-hole rock breaking technology, tunneling parameter optimization