Soil Stabilization by Ground Freezing

Widely popular throughout the rest of the world, ground freezing with liquid nitrogen is slowly becoming recognized in the United States as a viable way for the construction industry to stabilize soft soils. The technique is already used in the United States for micro tunnels and vertical shafts, and it is carefully being considered for horizontal shafts as well.

The photograph below shows a very large horizontal shaft in Singapore ready for excavation after a deep freeze.



Same tunnel during setup for the freezing operation:



The flow of liquid nitrogen to every lance is computer controlled. The operator can see a continuous display of the temperature profile of the tunnel.