Frozening clay, silt and sand are most suitable for the ORT-helical pile. It can be used also in size 0-40mm rubble. When positioning the flange under the frozen soil layers, the helical pile can be used for constructions without additional earth removal procedures or frost insulation. In more demanding purposes consider using proper ground inspection and construction civil engineer.
Preparation work
Before installing the foundation check the possible locations of water- and gaslines, sewers, telephone and electric cables. Your local utility company will assist you if necessary.
Getting started
The work will start by hitting an iron bar to the ground to the depth of at least 50 cm to find out possible larger rocks or bedrock. If such obstacles are found, take special procedures for their removal. In large scale construction it is preferred to make the inspection or survey of the site before installing the first helical pile.
Installing the ORT Helical Pile manually
Thehelical pile can be turned into the ground manually with the help of an iron bar. The use of an L-shaped turning tool makes the procedure easy in slopeside, near the surface and walls and in tight corners
Installing the screw with hydraulic engine
The helical pile can be turned in with a hydraulic engine found in vehicle lifters and diggers. Needed maximum moment (torque) in turning is 2000 Nm depending on soil properties.
The flange should be positioned when possible below the frozen soil layer. This secures the foundation against frost lifting.
Expansion part
The ORT helical pile foundation can be made to match the different founding depths by adding up to 6 meter long entension pieces into the helical pile foundation pole.
Things to consider
If the ground water level is less than 1 meter below the surface, it is recommended to fill the ORT heical pile with suitable concrete, rubble or polyurethane foam. Otherwise frozen water inside can fragture and break the pole.
The helical pile cannot be used in soil with rubble size over 50 mm.
The ORT helical pile foundation can be used in frozen homogenous soil. If the installation is done with a hydraulic engine can the foundation also be installed directly through asphalt.
In case large amount of helical piles are used they should the positioned in correct hight by turning the screws only clockwise. If necessary the piles can be cut to matching hight. The piles should not be turned counterclockwise unless that specific pile is to be taken away from the foundation.
When the construction is under ground water level or under water, the penetrating depth into the soil should be in hard and medium hard soil at least 2 meters and in soft soil 3 - 3,5 meters.