Envirocon is a recognized leader in applying specialty geotechnical solutions to a variety of civil and environmental applications. These applications include the installation of some of the longest and deepest slurry and reactive barrier walls in the United States to control and treat groundwater; and the installation of sheetpile containment and excavation support systems, soil mix walls, and innovative in-situ stabilization/treatment systems.
Vibrated Beam Slurry Walls are a recent addition to Envirocon’s resume of Geotechnical projects. This technique involves the driving of a specially designed wide flange beam section with a grout injection nozzle located at the base of the beam connected to a vibratory driver-extractor. The engineered beam is vibrated into the ground while injecting a self-hardening slurry to aid as a lubricant. The beam element is then extracted, creating a minimum 4 to 6 inch panel which is filled with the self-hardening slurry as the beam is retracted. The successive penetrations of the beam element in conjunction with the overlapping of the previous beam insertions, forms a continuous cutoff wall.
The integrity of the slurry wall is maintained using the following Quality Control measures:
- Verticality control of the beam during insertion;
- Overlapping individual elements by 6 inches;
- Use of a trailing fin located at the base of the beam to serve as a guide to follow the previous beam insertion;
- Injection of 100% of the panel volume with a self-hardening slurry;
- Use of a reservoir trench at the surface to serve as additional slurry volume to supplement any loss into the soil formations; and
- Real-time monitoring and documentation of all critical parameters during installation.
The Vibrating Beam construction method allows for work in confined areas with limited space for staging or above-ground mixing. In addition, since there is little excavation required, this technique also minimizes soil disposal costs, which can be costly when dealing with contaminated sites. Depths in excess of 50 feet are possible with permeabilities in the range of 10-8 cm/sec.