Construction pits

Waterproof earth retaining structures and groundwater control in any ground condition.

Contracting services

Construction pit

Figure: Construction pit with Geofrost walls.

Geofrost provides waterproof retaining structures in soils for construction pits with various depths and flexible shapes. The retaining walls can penetrate into rock or stop in soil.

Photo: Excavation of construction pit stabilized by Geofrost ground freezing.
The retaining structure is designed according to the Eurocode. Temperature, thickness, and geometry are adjusted to provide required capacity. The walls can be constructed without stiffeners or restraining elements, enabling continuous and efficient excavation.

Construction pit bottom

Figure: Excavation of construction pit stabilized with ground freezing and with waterproof frozen bottom.

Geofrost provides impermeable bottoms for construction pits. The frozen soil has good adhesion to other materials. Combined with retaining walls, the bottom slab provides stiffening. The bottom is frozen and fixed to buoyancy anchoring or made so thick that the weight balances the water pressure.

Foto: Geofrost construction pit bottom.
The bottom is constructed from above groundwater level, so that the pit is waterproof when excavation starts. If the bottom needs maintenance freezing during the construction period, the freezing pipes are reconnected after excavation.

Waterproof bottom is applicable when water ingress through permeable ground becomes problematic or pore pressure reduction in the surroundings cause risk for settlements.

Retaining wall

Figure: Cantilever Geofrost wall fixed in bedrock.

Photo: Insulation of Geofrost wall.
Geofrost provides temporary stable cut slopes and waterproof retaining walls. The retaining walls are particularly suitable in unpredictable soils like blocky moraine, talus or fills from rock blasting and in extra challenging ground such as landfill and old quay structures. It is easier to get through such grounds with single holes than with a continuous structure (i.e. sheet pile and diaphragm walls). The ground freezing ensures continuity of the wall between the single holes.

Photo: Geofrost walls crossing tram tracks in use.
Geofrost's retaining walls can be made continuously across tram tracks, cables and pipelines so these can be kept in operation during the construction period. Time is saved by avoiding temporary diversion lines in separate preparatory work contracts.


Figur: Frost som midlertidig understøttelse av hus.

Geofrost provides temporary underpinning of structures in connection with planned deeper excavation than the adjacent foundation.

Photo: Frostvegg under fundament.
Freezing pipes are drilled right next to the structure so that the frost can spread horizontally in under the foundation and ensure good vertical load transfer without any intervention of the structure to be underpinned. When the need for support ceases, the ground thaws and the foundation of the structure may remain uniform.

If refoundation is nevertheless necessary, the support wall is frozen wide enough so that the frozen ground directly below the foundation can be removed while the rest of the frost wall continues to support the ground behind. Thereby, refoundation can be carried out section-by-section.

Soil anchor

Geofrost provides temporary soil anchors with large surface area with full friction against the surrounding soil and thus a high capacity.

The anchors can be made in any ground conditions but get the highest capacity in water saturated ground. The anchors can be combined with different kinds of retaining walls and kept active as long as the wall has a function.

Ground improvement

Figur: Grunnforsterkning ved grunnfrysing,

Geofrost provides gentle temporary roads and working platforms on underground with insufficient bearing capacity like soft clay, quicksand, swamp and in winter climate even on water.

Photo: Pelemaskin på frostforsterket underlag.
Geofrost ground improvement may also be used for temporary access across vulnerable land that needs protection against mechanical wear. The frozen ground thaws naturally or may be actively melted after use.


Figure: Vanntetting av spunt med frost, ved hjørne og overgang til berg.

Geofrost provides water cut off as supplement to other constructions to achieve groundwater control, such as the transition between sheet piles and rock. We also provide waterproofing of leaking sections in sheet piles, secant piles and jet grout piles and cut off walls in coarse ground and fractured rock.

Ground freezing has good adhesive strength to other construction materials and can therefore be combined with steel, wood or concrete. The frozen soil completely seals toward any material and irregularities. Ground freezing is the most reliable method for complete sealing and groundwater control in soil.


Figure: Geofrost wall through rock fill.

Geofrost provides impermeable cores in rock fills which enables easy construction of cofferdams to afterwards drain the area for water.

The rock fill can be dumped directly on the bottom without replacement of existing soils. Drilling and freezing are easily carried out through the fill and further down through permeable layers and fissured rock, obtaining a completely waterproof cofferdam.


Any ground condition

Ground freezing works in all kinds of soil, independent of grain size distribution, permeability, and water content. It works in soils, such as moraine, glacifluvial deposits, peat, landfills and rocks of various quality. This makes freezing work equally well for transition zones between soil and rock and for soil containing block and boulders, with a 100 % waterproof result.

100 % waterproof

  • Full control of water inside and outside the Geofrost walls.
  • No wash out of fines with corresponding risk for instability and sink holes.
  • No leakage leading to pore pressure reduction and settlements.
  • No need for water infiltration and associated risk.
  • No extra sealing with cement or chemicals.
  • No influence zone outside the frost construction.
  • The earth support is installed from above groundwater level and is compeletly waterproof at start of excavation.

Efficient excavation to significant depth

The Geofrost wall's capacity is increased by increasing thickness, enabling great depths without stiffeners or anchors. The construction pit walls are ready when excavation starts, enabling continuous excavation and reduced construction time.

Free geometry

The freezing pipes are freely positioned, with any inclination, so the earth support gets the desired shape; as long as you can drill, you can freeze. Although the freezing pipes are placed individually, a continuous construction is established between them. The frozen body can therefore easily be established across railway tracks, pipes and cables and provide a waterproof sealing around bodies crossing through the wall. The Geofrost wall also becomes waterproof towards uneven surfaces of materials such as rock, steel, wood, concrete, plastic, etc.

Moderate energy consumption

Production of construction materials requires energy, either if it is freezing soil or it is producing steel or concrete. A comparison between sheet piles and Geofrost walls shows that the energy consumed by freezing over half a year is equivalent to just producing the steel for GU6N sheet piles. Almost two years of freezing is equivalent to producing the steel for AZ48 sheet piles. Comparing pile wall of steel pipes, Ø406x10mm, freezing can last nearly 3 years before consuming the same amount of energy.

Low CO2 footprint

Ground freezing has generally a low CO2 footprint. If Geofrost earth support is used in a project in Norway for one year, the CO2 footprint will be reduced by 80 % compared to a sheet pile wall of the type AZ-48 or equivalent.

What we deliver

We are a total supplier of retaining walls and impermeable construction pits by ground freezing and offer all related services within consulting and contracting.

We provide designed and engineered construction pits, ready for access and installation, or a limited scope adapted to project and client.

Consulting services

  • Project management
  • Sampling
  • Lab testing
  • Design and engineering
  • Numerical analyses
  • Design report, drawings, and specifications

Contracting services

  • Planning and procurement
  • Site management
  • Drilling and surveying
  • Pipe installation
  • Plant and equipment for brine freezing and nitrogen freezing
  • Instrumentation
  • Monitoring
  • Excavation

Where we operate

We offer our services worldwide.


Contact person

Anne-Lise Berggren, Ph.D., M.Sc
Senior specialist geotechnics
(+47) 95 29 29 30


If you have questions or would like more information, please contact us. With project info, we quickly provide price estimates.

Ground freezing since 1986.