Slurry walls create a below-grade barrier to block runoff and/or soil contaminants.

Using a soil-bentonite or cement-bentonite mix, slurry walls can be installed down to a depth of 20 m (long-arm hydraulic excavator) or even 26 m with specially modified equipment. Slurry walls are built by excavating a trench, removing existing material, and mixing it with an additive on site (cement/ bentonite) or replacing it with filler material when the excavated material is not reusable.

This technique is often used to contain the spread of soil contaminants or seal the core of a dyke. Its hydraulic properties as well as the orientation or width of the wall can be adapted to specific project requirements.