AB Diaphragms

Technology of construction and production of reinforced concrete piles with CFA technology

Reinforced concrete diaphragms

Execution of reinforced concrete diaphragm requires the engagement of special mechanization, with accompanying equipment, accessories and tools.

Reinforced concrete diaphragms are made with the help of MAIT HR 130 excavator with rigid connection by hydraulic guidance of the "Kelly" bar grapple.


Ancillary equipment used to perform reinforced concrete diaphragms:

  • Mortar for the preparation of bentonite suspension:

  • Sludge pump for pumping bentonite suspension from the tank to the excavation.

  • Grapple with which the excavation itself is performed, which is connected to the machine with a rigid connection measuring 250 cm x 60 cm or 45 cm.

  • Contractor concreting pipes with hopper:

Given the characteristics of mechanization, as well as the technology itself, the production of reinforced concrete diaphragm requires a working plateau that must be well planned, from wild material and rolled from 30MPa to 35MPa, over which to plan and also roll gravel or pave the terrain with reinforced concrete plates. The working plateau required for the movement of the machine must be min. 7m, other mechanization, such as auto-mixers, must also move along that working plateau, in order to approach the left side of the contractor during concreting, where it will not get stuck due to the process of making the reinforced concrete diaphragm.

The prepared terrain must be drained, both from the collection of atmospheric precipitation and from the extraction of water from the excavation.

With the work platform prepared in this way, the works will be performed with quality and without delays, with the correct leveling of the mechanization and the process of making the reinforced concrete diaphragm.



Excavation technology:

Before starting the excavation, it is necessary to make a lightly reinforced concrete continuous "L" inlet (guide) with a depth of 0.80 m to 1.00 m and a rate of 1.00 m to 1.20 m.

The quality of the performed introduction dictates later the appearance of the reinforced concrete diaphragm, its verticality and position.

At the marked place by the geometer, the mechanization is positioned, the grapple is leveled and the excavation itself begins. The excavation is performed from the top of the inlet to the projected elevation of the diaphragm depth. During the excavation, the bentonite suspension with sludge pumps is constantly and harmoniously added. Bentonite suspension serves to stabilize the excavation during excavation, the level of bentonite suspension must be maintained up to half of the inlet. The excavated material is disposed of on the side that must be removed with the help of an excavator or JCB during the excavation of the lamella. The material is loaded on trucks and transported from the construction site.


Reinforcement basket installation technology:

Before lifting the reinforcement basket, 3mm thick sheet metal is welded to it, which serves to separate the slats.

After the completion of the excavation, the installation of the already prepared reinforced basket is started, which has boundary sheets on it and which must be made according to the project documentation and welded according to the project. Thus, the stiffened reinforcement basket is safely raised to a vertical position with a crane and placed in a position above the inlet itself, where the excavation was previously performed. It then descends to the excavation itself at the projected elevation and position.

After lowering the reinforcement basket, the excavation is next to the boundary sheet, covered with loose materials from the excavation, preferably as consolidated as possible, using an excavator or JCB.


Lamella installation technology:

After the backfilling between the end of the excavation and the boundary sheet is completed, the contractor pipes are lowered through the reinforcement basket up to 30 cm from the bottom of the excavation. The diameter of the pipe is Ø245 in segments of 2.00 m and 1.00 m, which are connected to each other with cables. A funnel is placed on top of the pipe, which is fastened with a pipe cable.

The installation of concrete is approached after the installation of contractor pipes, the auto-mixer approaches the funnel and concrete the knife is made from the bottom to the top, which prevents the contact of the concrete mass with the sludge from the excavation itself, except for the surface layer itself, which is later finished. Concreting must last without interruption in order to avoid interruption of concreting, creation of "nests" in concrete or segregation of concrete itself. During the concreting itself, the contractor pipes should be immersed in the concrete mass of min. 2.00m. During concreting, the bentonite suspension is removed by gradually lifting the concrete with the help of sludge pumps and returned to the tank.

Geomechanical team

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