Vertical Barriers/Slurry Walls Bio-Polymer Trenches Permeable Reactive Barriers Soil Mixing Jet Grouting Wetlands Site Remediation Dam Grouting MGP Sites Levee/Dam Reinforcement & Repair

Vertical Barriers/Slurry Wall


Vertical Barriers or Slurry Walls (also known as Cutoff Walls or Slurry Trenches) offer a cost-effective solution to groundwater control problems. These barriers are constructed to intercept and impede the flow of fluids (groundwater, contaminants) underground and can be effective for site dewatering, underground pollution containment and seepage barriers under dams and levees. Constructed by excavating a narrow trench under an engineered fluid, the slurry trench technique permits the installation of deep barriers in all types of soil and groundwater conditions. Containment technologies such as slurry walls can eliminate the need for excavation and disposal of impacted soils and contaminants as well as costly shoring and dewatering associated with deeper removals.

Geo-Con's 500 plus installations include the construction of impermeable soil-bentonite, cement-bentonite and composite slurry walls. Geo-Con has also pioneered the use of alternative materials such as attapulgite clay, special cements and silicates for cutoff walls where site leachate conditions and incompatibility prohibited the effective use of bentonite. These techniques have been further modified in constructing cement-attapulgite, soil-attapulgite and cement-bentonite silicate cutoff walls.

For projects with site conditions that prohibit the use of deep (up to 80') slurry trenches due to soft unstable soils or high levels of contamination, there are alternatives to the conventional hydraulic excavator and/or clamshell method.


Where the risk of a trench collapse would be detrimental, or a structural wall is required, Geo-Con can use our DSM procedure to install a deep (up to 120') vertical barrier by continually injecting a slurry with increasing depth, thus mixing with the soils in-situ. This technique avoids the excavation of contaminated soils while installing an impermeable retaining wall.

Geo-Con has designed and installed barrier cutoff walls with permeabilities as low as 1 x 10-8 cm/sec and strengths as high as 400 psi. In-house engineers and slurry wall specialists have the necessary skills to develop mix designs to meet permeability and strength requirements to insure project specifications are met. Geo-Con has pioneered the innovative vertical barrier applications such as self-hardening, high strength and ultra-low permeability slurries.

Typical Vertical Barrier / Slurry Wall types and backfill mixes include:

  • Soil-Bentonite (SB) Walls
  • Soil-Attapulgite Walls
  • Cement-Bentonite (CB) Walls
  • Cement-Attapulgite Walls
  • Soil-Cement-Bentonite (SCB) Walls
  • Slag-Cement-Bentonite Walls
  • Composite Liner Walls


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