Slurry walls are used in various construction and engineering applications where the creation of a deep, watertight, and structurally stable barrier is necessary, for example in tunnel construction to stabilize the surrounding soil and prevent water ingress during tunnel excavation.
Slurry walls are typically constructed by starting with a set of guide walls, typically 1 metre (3 ft 3 in) deep and 0.5 metres (1 ft 8 in) thick. The guide walls are constructed on the ground surface to outline the desired slurry trench and guide the excavation machinery. Excavation is done using a special clamshell-shaped digger or a hydromill trench cutter, suspended from a crane.
Once a particular length of trench is reached, a reinforcing cage is lowered into the slurry-filled pit and the pit is filled with concrete from the bottom up using tremie pipes. The heavier concrete displaces the bentonite slurry, which is pumped out, filtered, and stored in tanks for use in the next wall segment, or recycled.
A Hungarian company was looking for a solution to pump bentonite in a deep construction site. Initially, high-speed pumps were used, but they did not deliver the desired performance.
The solution finally came with Tsurumi slow-speed pumps connected in series in a booster installation: The KRS2-150 is excellent for this abrasive application because it operates with fewer revolutions. The series connection provides the necessary power to pump the abrasive liquid over the required distance without any problems.
In a test installation, it was checked whether the solution actually worked in practice. The water containing bentonite was fed from a container about five metres up into the booster pump. It then pumped it through a 400-metre-long pipeline to the separation plant. The solution worked so well that the customer will now standardise this Tsurumi application.
In Cologne, Germany a new subway was built near the city centre. Before construction with a tunnel boring machine could even begin, the surrounding buildings had to be stabilized by a injection of a cement suspension. This process is called jet grouting. Two shafts were installed. From here, work was carried out to stabilise the foundations of the adjacent residential buildings. Depending on the shaft, different numbers of transverse boreholes with a depth of up to 50m were drilled. The boreholes were then grouted with a cement suspension.