Sealing off the surrounding groundwater is a factor of decisive importance when excavating pits. Any inflow of water or soil must be reliably prevented. Special precautions are needed to protect personnel and equipment against such “surprises”. Sheet piling is one method used; injection seals are another, or the groundwater level can also be lowered. Often enough, these precautions do not suffice on account of adverse soil conditions. Special solutions are needed in such cases, such as freezing the soil with liquid nitrogen.
Liquid nitrogen is injected into the soil through freezing lances. The liquid nitrogen first flows downwards through the inner pipe, absorbing heat in the process and evaporates. The resultant cold gas emerges from the lance through the annular gap in the outer pipe. This gaseous nitrogen also transfers some of its tangible cold to the soil. The water contained in the soil freezes, forming a solid body of ice around the lance. With time, the bodies of ice around adjacent lances grow together to form a solid wall sealing the excavated pit.
Your advantages at a glance
- Quick and simple installation,
- Short freezing times due to the large difference in temperature between refrigerant and soil,
- Eco-friendly method (no chemicals, noiseless, no effluent),
- High availability (liquid nitrogen is available in virtually unlimited quantities),
- Solid bodies of ice can be created in any shape and size