Well Foundation
Installation of a prefabricated well foundation:
- The cutting edge is placed at the planned location of the foundation.
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Excavation of the soil begins within the area of the cutting edge.
- The first reinforced concrete casing segment is placed on it and earthwork continues, causing the segment to start sinking together with the cutting edge.
- Subsequent casing segments are then placed until the planned depth is reached.
- The bottom of the well must be sealed with a waterproof concrete layer; this is the bottom plug.
- The inside of the well is filled with lean concrete or sandy gravel.
- Finally, a load-bearing head plug is made from a reinforced concrete slab on top.
Installation of a steel-cased well foundation:
- The steel casing wall is sunk.
- The soil is excavated using a well-digger bucket machine.
- Concreting begins, filling the well in stages.
- Simultaneously with the concreting, the steel casing wall is continuously pulled out.
- The well foundation bodies are typically connected by a grid footing.
Pile Foundations
Precast piles can be used in loose soil layers and for maximum foundation depths of 10-12 meters. These piles have various cross-sections with side widths of 30-40 cm and a steel-tipped point. The precast reinforced concrete piles are driven into the ground using pile driving, pile vibration, soil flushing, or a combination of these methods.
Drilled Piling, Without Casing (e.g., Soil-Mec): As part of the Soil-Mec process, a guide pipe is installed in the upper section (3-5 m) of a 80-150 cm diameter bore made with a bucket auger to prevent collapse. Bentonite slurry performs the same function in the lower part of the bore. The pre-prepared reinforcement cage is placed into the finished bore, followed by concreting.
Drilled Piling with Recovered Casing (Benoto): In the Benoto process, a casing pipe with a minimum diameter of 80 cm is driven into the soil using rotation and up-and-down movements. Simultaneously, soil is continuously excavated from inside the pipe. This is followed by the placement of the reinforcement and the concreting. The casing pipe is continuously recovered as the concreting proceeds.
Driven Piling with Recovered Casing (Franki): As part of the Franki process, a casing pipe is placed at the planned location of the pile and filled with concrete to a height of 1 meter. The hardened concrete plug is compacted (rammed) to drive the casing pipe into the ground to the desired depth. At the end of the process, the concrete plug is driven out of the bottom. The reinforcement is then placed, and layered concreting begins. Simultaneously, the casing pipe is continuously recovered using constant up-and-down movements.
Formation of the Pile Cap: The upper part of the completed piles is trimmed. A box-like pile cap is then constructed around the exposed and splayed reinforcement by placing additional reinforcement and formwork, concreting, followed by the removal of the formwork.
Diaphragm Wall
A diaphragm wall is typically 40-120 cm wide, 6-40 meters deep - usually extended below the load-bearing soil level, which ideally is also a waterproof layer.
Better cooperation with the supported soil can be increased by anchoring it back.
Diaphragm wall construction process:
- Construction of the guide beam;
- Excavation of soil from a single panel section in the width of the wall;
- Simultaneously, diaphragm wall slurry (grout) is pumped into the place of the excavated soil;
- Reinforcement cage is lowered into place;
- Concrete is poured from the bottom up, continuously displacing the slurry.
