How many meters should the blower be installed during tunnel construction?

Tunnel construction ventilation should be able to provide the minimum air volume required for various operations in the tunnel, and each person should supply 3m³/min of fresh air. When using internal combustion engine operation, the air supply volume should not be less than 3m³/min.

When the single-head excavation length of tunnel construction exceeds 150m, mechanical ventilation must be adopted.

The wind speed of tunnel construction ventilation shall not be less than 0.15m/s in full-section excavation, and shall not be less than 0.25m/s in the tunnel excavated in sections.

The installation of the air duct should meet the following requirements:

1 The separate press-in type air inlet nozzle or the suction type air outlet nozzle should be located outside the cave. The former should be 20m away from the entrance of the cave, and the latter should be made into a chimney.

2 The distance between the ventilation pipe and the excavation face should be determined according to the specific conditions. The distance between the outlet of the press-in ventilation pipe and the excavation surface shall be determined by calculation.

3 When using mixed ventilation, when one group of fans moves forward, the pipes of the other group of fans should be extended accordingly. The staggered distance between the two sets of ventilation pipes shall not be less than 20-30m.

4 The installation of the ventilation pipe should be smooth, the joints should be tight, and the average air leakage rate per 100m should not be greater than 2%. The radius of the elbow shall not be less than 3 times the diameter of the ventilation pipe. 5 When a hose is used for the ventilation pipe, a reinforced air duct should be used for the part close to the fan.