Slurry walls are constructed using either cement-bentonite or soil-bentonite based slurries to produce an in ground low permeability barrier.

Common uses

Create barriers to groundwater flow
Encapsulate contaminated groundwater and leachates
Prevent the lateral migration of gas
Typically installed for dam control, flood water control and landfill sites

Process

A cement-bentonite slurry cut-off wall or slurry trench wall is typically excavated using a backhoe while simultaneously pumping a cement bentonite mix into the trench often to depths in excess of 25m. Once cured, the slurry cut-off wall provides a permanent low permeability barrier to groundwater and leachates.

Where gas migration is the issue a high-density polyethylene membrane is placed in the wall in panels connected with an interlock system.

Soil bentonite walls are constructed in a similar manner using a backhoe excavator but using a temporary bentonite slurry to support the excavation while surface mixing the excavated soil with bentonite and potentially imported clay material before backfilling the trench and displacing the temporary bentonite slurry.

Advantages

Quick installation
Low cost solution for low permeability barriers
Permeability 1x10-9m/sec
Can be designed to provide resistance to a range of heavy metals and organic contaminants including volatile organic compounds (VOCs), hydrocarbons, diesel, solvents and tars

Quality assurance

Keller has decades of experience installing slurry walls.

A specially developed mix combined with a strict quality control ensures consistency and a product installed and designed to withstand the test of time.

Samples from the top and bottom of the trench are taken daily and a series of testing can be done including slump, specific gravity, bleed, shear strength and pH.