2.3.4 Control of Driving Parameters in the Initial...
1）Idling position
The cutter head does not need to rotate，no mud，Jack propulsion speed is 10 mm/min.
2）Strengthened area
（1）Keep the incision water pressure：because the shield is in the strengthened area，the incision water pressure should not be set too high.According to the actual working conditions，make appropriate adjustments during construction.
（2）controlling the propulsion speed：in order to ensure that the shield can grind the soil reinforcement area normally，prevent the suction of the mud discharge pipeline from clogging，control the propulsion axis and protect the cutter head，the propulsion speed should not be too fast in the actual crossing process，so that the shield machine can move forward slowly and steadily，the propulsion speed is controlled in 3 mm/min，and the change of cutter head torque is observed at any time，and the propulsion speed is adjusted in time.
（3）Controlling the tunnel axis：in the initial construction，because the synchronous grouting cannot be opened in time，the slurry on the front of the shield can easily run back，resulting in the“floating”of the shield，so the propulsion axis should be slightly lower than the design axis，which is generally suitable for-30 mm.