Diaphragm Wall

Cut-Off Wall is one special type of retaining structure for deep excavation pitches, to keep buildings, roads and the land around a construction plot from sliding and being destroyed by this as result.

The construction is undertaken, depending on the prevailing soil-conditions, by means of equipment which will be chosen by the special-foundation contractor: For alluvial the equipment will be mainly Diaphragm-Grabs, whereas the equipment will change to Trench-Cutter Systems when Rocks have to be penetrated. Here, again a diversification has to be mentioned; the trench is supported by thixotropic support-fluids or by polymer fluids:

Very soft and weathered rocks and alluvial can be excavated with Trench-Cutters using Standard Type Cutter-Wheels;

If alluvial, hard cohesive soils and medium hard rock is encountered, then Hybrid Cutter Wheels are used.

If hard rocks below q_u = 120 Mpa are encountered, Round-Shank Cutter-Wheels are employed.

Rocks above this hardness are being cut bye Roller-Bit Cutter-Wheel, whereby the cutter-frame has to be surcharged with respective additional loads to suffice the requirements.

Moreover, there are several sizes of Trench-Cutters for more or less challenging soil conditions.