Ground-freezing/soil-freezing pipes have been used in construction for more than 100 years for soil stabilization, to cut off groundwater, and to support excavation in unstable soils.
Small diameter freeze pipes are installed in the ground, usually vertically in a grid configuration. As a coolant, such as brine or liquid nitrogen, is pumped in a continuous loop into the grid, water in the surrounding soil begins to freeze and eventually forms a wall. The resulting soil wall is roughly the strength of concrete.
One of the main uses of ground freezing is in deep shaft excavation. It is also used extensively in mining, foundation excavation, and pump station construction, as well as environmental remediation and groundwater cutoff. Its best use is for projects where excavation support and groundwater cutoff are required, especially for deep and large excavations.