slurryväggar

Slurry walls, known in Swedish as "slurryväggar," are a form of excavation support system used in civil engineering projects. They are constructed by excavating a trench and immediately filling it with a bentonite-water slurry. This slurry, due to its high viscosity and thixotropic properties, prevents the trench walls from collapsing and keeps groundwater out.

The construction process typically involves a guide wall, a common reinforced concrete structure built at ground level to guide the excavation equipment. Excavation is carried out using a grab, a clamshell, or a specialized milling machine, which removes soil and creates the trench. As excavation proceeds, the bentonite slurry is continuously added to maintain a stable trench. Reinforcement cages, usually steel rebar, are then lowered into the excavated trench filled with slurry. Finally, concrete is poured into the trench through tremie pipes. The heavier concrete displaces the lighter bentonite slurry, which is then recovered and recycled.

Slurry walls are often used for deep excavations in urban areas where space is limited and stability is critical. They are particularly effective for constructing underground structures such as basements, subway stations, tunnels, and retaining walls. Their primary advantages include their ability to withstand significant hydrostatic pressure, their impermeability, and their suitability for use in unstable soil conditions. The construction process can also be relatively quiet and generate less vibration compared to other excavation methods.