Vertical panels are excavated under stabilising slurries using mechanical/hydraulic clamshell grabs or hydromill cutters to form a continuous cut-off, retaining and/or structural wall.

Diaphragm walls illustration

Common uses

Diaphragm walls are ideally used in congested areas or where the excavation depth is very deep which would otherwise required excavation of much greater soil volumes to provide stable battered slopes
Particularly suited to deep basements, underground rail stations, rail car unloaders, tunnel approaches, pumping stations and the like
Support of open or top down excavations
Create barriers to groundwater flow
Provide load bearing elements (LBE Barrettes)

Process

Diaphragm walls are constructed using grabs or cutters to create a narrow trench excavation into the ground. The trench is supported be an engineered slurry. Generally diaphragm walls are made from reinforced concrete, though unreinforced walls can also be used. Joints in adjacent panels are formed using either an over-cut (secant) technique or via temporary stop-ends.

Keller offer diaphragm walls in a range of thicknesses from 450-1500mm which can be excavated to depths of 100m.

Advantages

Can be installed close to existing structures and in restricted headroom
Can be used in conjuction with top down construction

Quality assurance

Keller has a fleet of specialist wall excavation and construction equipment to complete all types of diaphragm wall and load bearing elements (LBE barrettes).