Diaphragm Walls in Concrete and Special Mixtures
The diaphragm wall technique allows for the construction of structural and hydraulic works, serving temporary or permanent purposes. It involves excavating a rectangular section of soil. The rectangular section can have a width ranging from a minimum of 40 cm to a maximum of 120 cm, and the excavation usually occurs in the presence of a stabilizing fluid, typically bentonite mud. Diaphragm walls can be used for:
- Diaphragm walls to protect deep excavations, even exceeding 20 m; in these cases, it is essential to provide the diaphragm with a series of constraints (tendons or struts); also alongside existing buildings
- Foundation diaphragm walls
- Diaphragm walls for bank protection along rivers and canals
- Diaphragm walls in special mixtures for hydraulic sealing, confinement, and waterproofing
Diaphragm walls are constructed using hydraulic excavators equipped with hydraulic or cable-operated clamshell buckets. The excavation starts from ground level along alignments properly delimited by the formation of specific guide trenches in reinforced concrete. Depending on their use, the execution process can occur in different ways.
Concrete Diaphragm Walls (for excavation protection – foundation)
The support of excavation walls is ensured through the use of bentonite or polymeric mud. Structural diaphragm walls are typically reinforced with pre-assembled steel cages, which are lowered into the hole using a service crane, and the jetting is done through a jet tube that allows filling the hole from bottom to top (contractor method).
Plastic Diaphragm Walls
Unlike concrete diaphragm walls, during the excavation phase, plastic diaphragm walls do not use any stabilizing fluid (bentonite or polymeric mud) but directly use the waterproof and self-hardening mixture, generally consisting of: water, cement, and bentonite. Plastic diaphragm walls are not reinforced.
Operational Unit for Diaphragm Walls
To set up an operational unit for diaphragm wall execution, the following are required:
- Bentonite silos
- Mud mixing plant
- Mud storage tanks
- Desanders for mud recovery
- Drilling rig equipped with hydraulic or cable-operated bucket
- Service crane
- Wheeled loader
Palingeo has 5 operational units.
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