Anvendelse af stabiliseringsudstyr

Industrial and parking area

Kivikko is situated in the eastern side of Helsinki, the capital of Finland. Approximately 12 ha of the lots and streets in Kivikko are situated on soft swamp and are completely unsuitable for construction purposes. In this area two separate stabilisation tests were carried out, in the first area mass stabilisation only and in the second mass and column stabilisation.

In the first area mass stabilisation was applied to a depth of 3 metres. The result was a solid platform 3 metres deep that will serve as the foundations for a parking area.

The second area treated, using the column and mass stabilisation methods, will serve as a building area for industrial units. The required stability and carrying objectives were reached; the results provide a very good example of the possibilities that can be achieved with stabilisation.

Sport field foundations

In Finland, where temperatures vary between -40 and +35°C, many sport fields have problems with freeze and thaw. A sports field in Luopioinen, in the middle of Finland, is a typical example of this problem. For this reason it was chosen as a pilot project.

After laboratory tests, the fly ash from a paper mill s power plant, and the fibre clay from a local mill were added to the soil. During the laboratory research it was observed that a homogenous mix of the materials is particularly important. The ALLU PM Power Mix was chosen as the mixing device, its pulverizing and mixing capabilities provided excellent results. The fibre clay and fly ash were spread on the surface. The Power Mix pulverized and mixed the clods of clay, while at the same time blowing the binding agent from the compressed tank into the mass. The field was finished in September 2002. Now after the experience obtained from Luopionen other projects are being explored.

High speed railroad construction

One of the recent contracts where the ALLU Stabilisation System has been in operation, is a high speed railway line construction site, on soft peat in southern Finland.

The ALLU Stabilisation System is used to strengthen the soft peat creating a working platform for a 70 tonnes piling rig. The binder agent provided by the ALLU PF is mixed using the ALLU PM (in-situ) to a depth of 5 m.

Previously it would have been necessary to excavate the entire area and fill the void with stone, this would create all sorts of problems for the contractor, finding a suitable area to deposit the excavated material and also sourcing the stone as fill. The second possibility would have been to build a bridge.

Foundation of the road junction

The project was to build up the foundation for the road junction by mass stabilising. The total area was 1800 m² quite soft peat. The project was done in Tampere, Finland.

The stabilising work was done with ALLU PM 300, equipped with peak drums, to be apple to crush the ice clumps, while the surface of the swamp was already frozen.

The working method used was stabilising in blocks 4 m x 5 m and 3 m deep. In part of the area 100 kg/m³ cement was used as a binder and the other amount was 150 kg/m³. The binder was fed into the material through pipe by compressed air.

After stabilising each block the geo textile was unrolled over the treated material and over the geo textile 300 mm of gravel layer was formed. The average working capacity of 7 blocks in 8 hour s day was reached. This included also the spreading of geo textile and gravel.