Compressed Air Method
Definition - What does Compressed Air Method mean?
The compressed air method is used in pipe jacking to provide a positive pressure on the face of the tunnel. The pressure supplied by the compressed air prevents groundwater from entering the tunnel, thus building up in the pipe and damaging equipment.
The compressed air method is one alternative that can be used to enable trenchless construction projects to be conducted safely and efficiently at depths below the groundwater table.
Trenchlesspedia explains Compressed Air Method
In trenchless construction projects below the groundwater table, the water pressure from the surrounding ground can push large volumes of water into the tunnel. Compressed air supplied to the front face keeps the tunnel under a positive pressure and water out. When the tunnel is pressurised, workers can enter and work in the pipe jacked tunnels to remove large boulders that cannot be extracted by the screw conveyer.
The compressed air method is an alternative to the pressure balance method where slurry is pumped to the face of the cutting head to provide a positive pressure on the tunnel face.