The significance of shielding generation and arrival

The meanings of shield initiation and shield arrival are as follows:

1. Definition of shield launching: It means that the shield is positioned on the installation shaft or through the shaft from the main shield machine, and the cutter head advances forward and penetrates into the rock, and advances along the design line until the conditions for removing the negative ring are met.

2. Definition of shield arrival: When the shield machine arrives to pass through the shaft or dismantle the shaft, it must complete the positioning measurement, install the receiving frame, install the segment connecting device and treat the tunnel entrance before arrival.