Slurry Walls is the term used to describe the method by which sub-surface barriers designed to inhibit the transmission of water and pollutants are formed in soils.
Slurry Walls are installed as trench excavations whereby in-situ materials are removed and replaced by a relatively impermeable backfill material. The trench is excavated through a supporting fluid, usually bentonite or bentonite cemnt suspension, over the depth designed for the barrier. The supporting fluid may be replaced in the backfilling operation, as with bentonite, or may be self hardening, thereby eliminating the need for backfilling but requiring the removal of excavated material, as with bentonite cement.
Mayfield, New South Wales
Frequently, this method is used as a water barrier but it also has environmental applications in the containment and control of contaminants and pollutants. along the trench in pursuit of the continuing excavation.
Objectives of Slurry Wall installation:
Mayfield, New South Wales
Shallow Slurry Wall excavation is most frequently effected by hydraulic excavator. For increased trench depths, specially fabricated long arms are fitted to large hydraulic excavators which allow trench excavation depths of up to 25 metes. Greater excavation depths can be achieved by clamshell excavation, either as the prime excavation unit or in conjunction with hydraulic excavators.
Mayfield, New South Wales
Soil Bentonite cut-offs are created by backfilling the trench excavation following the mixing of the excavated soil with added soil components to create a backfill material with an appropriate particle size grading and hence low permeability.
Cement Bentonite cut-offs are created simply by leaving the excavation support fluid to set in the trench.
