Fresh Kills Landfill
Cutoff Wall Project
Staten Island, New York

Installation of approximately 776,000 vsf of soil-bentonite and 529,000 vsf of cement-bentonite cutoff walls around the perimeter of two active sanitary landfills within the Fresh Kills Landfill Complex in Staten Island, New York. All total, approximately 1.3 million vsf (almost 8 miles) of cutoff wall was installed at depths ranging from 20 to 62 feet.

Intense coordination was required between the NY DOS, the General Contractor (Tully Construction), the design engineers and the local labor unions to ensure timely completion and no interruptions to the 24-hour a day, 6-day a week, landfill operation.

In certain locations during soil-bentonite installation, the density of the soil-bentonite backfill was found to push the trench walls apart creating unexpected widening of the outboard site of the trench. The situation created the trench to widen up to 13 feet in certain sections and forced the trenches to be abandoned until a remedy could be found. Geo-Con provided the engineering solution by substituting cement-bentonite in lieu of soil-bentonite in areas where the slurry trench had already widened and where stability studies indicated there was a likelihood of further trench movement. Soil-bentonite was continued in areas where wall movement had not occurred or movement was not expected.

• Start: 9/1/96
• Completion: 2/98