 |
 |
 | |
    |
|
GEOTECHNICAL CONSTRUCTION Slurry Cutoff Wall Geo-Con installed a 185,000-square-foot slurry wall at the U.S. Army Corps of Engineers' Winfield Lock and Dam in Winfield, West Virginia. The 55-foot-deep slurry wall was constructed to dewater an excavation for a new lock.
The soil-bentonite slurry trench was keyed into the underlying bedrock using a hydraulic excavator. The primary tool used for the excavation was Geo-Con's rock ripper bucket, which featured integral ripper/chisel points allowing easy penetration into hard soils and soft rock. Once the desired depth of the trench was reached, the bottom was cleaned of unwanted sediments using the excavating bucket. The depth of the completed slurry trench was measured every 20 lineal feet.
Bentonite slurry was produced onsite in Geo-Con's custom designed, high-speed colloidal mixing plant. The five-cubic-yard mixer had the capability of producing up to 500 gallons of hydrated bentonite slurry per minute, without storage ponds. The materials excavated from the trench were utilized for the slurry backfill.
Geo-Con completed a slurry wall mix design to determine the likely performance of the slurry cutoff wall. A mix design submittal document was prepared to determine a recommended proportioning of ingredients for a stable, low-permeability bentonite blend. Samples of three site soils, commercial bentonite clays and Kanawha River water were provided to a private, independent laboratory to develop the design mix. It was determined that material excavated from the trench, properly blended and mixed with bentonite slurry, made an acceptable ingredient for the soil-bentonite backfill.
|
 |
