CFA piles
Soil Displacement Piles (SDP)
DSM columns
Injection micropiles

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CFA piles
CFA piles are drilled into the ground with the use of an auger equipped with a pipe for pumping in the concrete during pile driving. Once the formation level has been achieved, the concrete is poured through the pipe, while at the same time the auger is being lifted. Pumping in the concrete under pressure prevents the soil in the side surface and pile base from getting loose. The pile shaft is carefully filled with concrete and afterwards
a steel reinforcement basket is introduced. Strict adherence to technological regimes guarantees high quality of piling work, therefore the whole process is monitored
by a special system in which the drilling rig is equipped. Parameters such as auger penetration, concrete pressure and concrete flow are controlled on a continuous basis
to ensure proper pile diameter. The main advantage of the technology is that the whole work proceeds very quickly in comparison to the conventionally driven piles.
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Soil Displacement Piles (SDP)
Soil Displacement Piles (SDP) are driven in a vibration-free way with no dynamic impact
on the surrounding. The process consists in drilling an opening in the ground while simultaneously pushing the soil to the sides, without removing the spoil. As a result,
the ground on the side surface is additionally compacted, thus ensuring better pile-soil contact parameters. The soil under the pile base is further compacted by introducing an auger to the ground, where vertical force is applied by means of special pulley blocks.
When the required drilling depth has been reached, the auger is lifted while the concrete is being poured in. The auger continues to rotate to remove any falls of the soil, pushing the soil to the outside. When the opening has been filled, a reinforcement basket
is introduced. The SDP technology has been developed to take advantage of the small diameter of the piles by obtaining appropriate pile-soil interaction parameters.
The technology complies with environmental requirements as there is no need for mining, transporting or utilising the frequently contaminated spoil.
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DSM columns
The Deep Soil Mixing (DSM) technique is used to reinforce weak ground. DSM improves
the mechanical properties of the ground, which as a result of mixing takes the form
of a so called soil-cement. In Deep Soil Mixing, a special mixer mounted on a drilling rod
is introduced into the ground. The shape and size of the mixer depend on the type
of reinforced soil, but usually it consists of cutting and mixing parts. Drilling is shock-free and is facilitated with cement grout flowing out of mixer nozzles. Once the required drilling elevation has been reached, a DSM column is formed. This is the crucial point
of the process: the rotating and hauled mixer ensures proper mixing of the cement grout with the soil. The composition and quantity of the grout pumped in is adjusted
to the required properties of the soil-cement based on the expected functions
of the columns. The DSM technology is environment friendly, with non-hazardous materials used and practically no excavated material produced. The whole process of forming DSM columns is fully controlled. During the drilling operation, column cards are printed out from the computer integrated with the drilling rig, specifying the date and time of work, penetration of the mixer below the working level, column length, mixer rotation rate, mixer pulling up rate, and quantity of grout pumped per column. Column strength is subject
to standard laboratory stress testing.
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Injection micropiles
Injection micropiles are used for building new as well as strengthening existing foundations. In all cases, the micropile technology is based on the same percussive
and rotational drilling with the use of special rods and simultaneous injection of cement grout. The first section of the pipe rod is equipped with a cutting bit. Rods may be expanded by adding new sections and connecting them with couplings. Cement grout
also acts as a drilling fluid, creating a carrying section around the rod. An anti-shrinkage agent is added to the cement grout. The main factor allowing for penetration of the rod
is the torque and the vertical thrust of the drilling unit of the machine. Percussive drilling
is applied only if there are any obstacles in the ground, such as stones or rubble,
but avoiding any substantial shocks.
With this technology of drilling, no craters are created around the pile – on the contrary, grout penetration causes petrification of the soil around the pile shaft.
Another advantage of the solution is the possibility to combine rods of different lengths, which allows for using mini-drilling rigs in locations where access is difficult, e.g. low cellars. The special couplings ensure rectilinearity of the piles and high buckling resistance. The overall simplicity of the solution which drilling with concurrent grout injection ensures high productivity per shift. Another advantage is simple shaping of the pile cap by means of cutting the rod and welding a steel plate onto it.
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