Ground freezing

Ground freezing is a construction technique used in circumstances where soil needs to be stabilized so it will not collapse next to excavations, or to prevent contaminants spilled into soil from being leached away.^[1] Ground freezing has been used for at least one hundred years.

Pipes are run through the soil to be frozen, and then refrigerants are run through the pipes, freezing the soil.^[1] Frozen soil can be as hard as concrete.