When would it be appropriate to use slurry trench walls?
Slurry walls are used to contain contaminated groundwater, divert uncontaminated groundwater flow, and/or provide barriers for groundwater treatment systems. Slurry walls are placed at depths up to 200 feet and vary in thickness from 2 to 4 feet.
Are slurry walls permanent?
In addition to serving as a stabilizing fluid to maintain an open trench during excavation, the cement-bentonite slurry remains to set up and form the permanent cutoff wall.
What is the purpose of the slurry wall?
A slurry wall is a civil engineering technique used to build reinforced concrete walls in areas of soft earth close to open water, or with a high groundwater table. This technique is typically used to build diaphragm (water-blocking) walls surrounding tunnels and open cuts, and to lay foundations.
What types of projects could a slurry wall be used for?
Thick walls can be produced that stand high load strength. Excellent for seepage and water control, slurry walls are used extensively for dams, sewage and for holding tanks. Slurry walls are also known as known as continuous diaphragm walls or seepage cut-off walls.
How slurry works as a wall describe it?
Slurry walls are deep wall structures made of concrete, reinforced concrete or binding agents in the building ground. They have a static or sealing function. For their production trenches are excavated in panels. A support fluid, usually bentonite suspension, prevents the soil around the trenches from caving in.
How does bentonite slurry work?
As a swelling clay, bentonite has the ability to absorb large quantities of water, which increases its volume by up to a factor of eight. This makes bentonite beds unsuitable for building and road construction. However, the swelling property is used to advantage in drilling mud and groundwater sealants.
What is slurry trench wall?
A slurry cut-off wall or slurry trench wall is typically excavated using a backhoe (or grab) while simultaneously pumping a hydrated cement bentonite mix into the trench to depths in excess of 25m. Once cured, the slurry cut-off wall provides a permanent low permeability barrier to groundwater and leachates.
What materials are used in slurry wall?
What is the purpose of bentonite slurry?
Bentonite slurries are known to perform the following pivotal functions: a) Support the excavation by exerting hydrostatic pressure on its walls i.e. to prevent the collapse or retain an area. b) Remain in the excavation, and not flow to any great extent into the soil thereby acting as a sealant.
Why bentonite slurry is used during boring?
Bentonite is a very fine-grained clayey material having a high percentage of montmorillonite material. Bentonite clay is a mined product. Usually, two types are there – Sodium based and Calcium based. Bentonite slurry shall be used for stabilizing the sides of the pile borehole.
What is cut-off wall?
Cut-off walls are predominantly to provide an embedded low permeability barrier to mitigate the flow of groundwater and any contaminants that it may contain.
How is a slurry wall used in construction?
The construction of slurry walls involves the excavation of a vertical trench using a bentonite-water slurry to hydraulically shore up the trench during construction and seal the pores in the trench walls via formation of a “filter cake” [3, p. 2-17].
How big is a slurry wall in feet?
The construction of slurry walls involves the excavation of a vertical trench using a bentonite-water slurry to hydraulically shore up the trench during construction and seal the pores in the trench walls via formation of a “filter cake” [3, p. 2-17]. Slurry walls are generally 20 to 80 feet deep with widths 2 to 3 feet.
Who was the engineer for the slurry wall?
According to Arturo Ressi, an engineer who worked on construction of the barrier back in the mid-1960s, the survival of the slurry wall was a real blessing.
Which is better a diaphragm wall or a slurry wall?
Slurry wall construction cost for cut-off barries is considerably cheeper than diaphragm wall construction for deep excavations. The differences arise mainly from construction method differences. In cut-off walls construction is much quicker as a continuous trench is excavated and backfilled and reinforcement cages are seldomly used.