DiaphragmWänden

DiaphragmWänden, often translated as diaphragm walls or slurry walls, are a type of underground structural system used in civil engineering. They are constructed by excavating a trench in the ground while simultaneously supporting the trench walls with a fluid, typically bentonite slurry. This slurry, a mixture of bentonite clay and water, creates a hydrostatic pressure that prevents the trench from collapsing.

The construction process involves digging a trench to the desired depth and width using a mechanical grab or a hydraulic grab. As the excavation proceeds, the trench is filled with bentonite slurry. Once the excavation reaches its final depth, reinforcing steel cages are lowered into the trench, and concrete is then poured using a tremie pipe. The concrete, being denser than the slurry, displaces the slurry upwards, forming a continuous, impermeable concrete wall. The displaced slurry is then pumped out and reused.

Diaphragm walls are highly effective in situations requiring deep excavations, especially in soft or unstable soils, or where groundwater control is critical. They are frequently used as retaining walls for basements, as cut-off walls to prevent groundwater flow into an excavation, and as foundations for bridges and other structures. Their primary advantage is their ability to create a strong, waterproof barrier in difficult ground conditions, minimizing ground settlement and water ingress. They are a permanent structural element and can withstand significant lateral earth pressures.