slurryvägg

A slurry wall, known in Swedish as a slurryvägg, is a subterranean structural element used in civil engineering for various purposes, primarily in water-retaining and earth-retaining applications. It is a trench, excavated in the ground and kept open by a bentonite-cement slurry. The slurry, a mixture of water, bentonite clay, and often additives, exerts hydrostatic pressure, preventing the trench walls from collapsing.

The construction process involves excavating a trench to the desired depth and width, typically using a clamshell grab or a specialized trenching machine. As the excavation proceeds, the trench is continuously filled with the bentonite slurry. Once the trench is fully excavated, reinforcement cages, often steel rebar, are lowered into the slurry-filled trench. Finally, concrete is poured into the trench using a tremie pipe, displacing the lighter slurry upwards. The concrete then forms a continuous barrier, effectively creating a solid wall within the ground.

Slurry walls are commonly employed in deep excavations for basements, subway stations, and tunnels to prevent groundwater inflow and support surrounding soil. They are also used as impermeable barriers to contain contaminated groundwater in landfill sites or industrial areas. The effectiveness of a slurry wall lies in its ability to create a continuous, watertight structure with high structural integrity. The bentonite slurry not only stabilizes the trench during construction but also contributes to the impermeability of the final concrete wall by forming a low-permeability filter cake on the trench walls.