In general, the local community supports the selected
remedy, particularly the creation of property that will lend
itself to development. The site is suitable for commercial development, and the NYSEG and AECOM are working with
the Department of Environmental Conservation to obtain
an environmental easement that will allow the property to
The site is underlain by four stratigraphic units. The top
layer comprises a generally thin layer of loose to compact sand
and gravel fill with concrete fragments, coal, and asphalt.
Next, loose to somewhat compact fine sand and silt generally
extend to depths of about 5 ft. This stratum is interpreted to
be alluvium. Loose to somewhat compact gravel and sand,
which also are interpreted to be alluvium, extend to depths
of 17 to 22 ft. Beneath the gravel, medium to stiff clay serves
as a continuous confining layer.
Index testing of representative samples indicated that
the gravel stratum contains 8 to 26 percent fines capable
of passing through a no. 200 sieve (mesh openings of
0.075 mm). The fines content in this stratum tended to decrease with depth, meaning that the soil has fewer fine particles at depth and so becomes more permeable. Tests of the
Atterberg limits, which provide a basic measure of the nature
of fine-grained soils, indicate that the gravel fines have some
plasticity, the plasticity indexes ranging from 0 to 9 percent.
Geotechnical test borings were made using hollow stem
augers and split spoon sampling. On the basis of consistent
standard penetration test blow counts and the judgment of
the driller, it was inferred that the natural soils at this site did
not contain significant cobbles or boulders. Groundwater at
the site typically occurred at a depth of about 6 ft.
ISS bench-scale studies were performed by KEMRON
Environmental Services, Inc., which has its headquarters
in Vienna, Virginia. The primary goals of the bench-scale
treatability studies were to confirm the feasibility of ISS as a
remedial process at this site and to guide the selection of ISS
reagents to achieve the required performance criteria in the
field. The bench studies focused on reducing the hydraulic
conductivity of the gravel soil layer. This outcome was con-
sidered of overriding importance to the success of this project.
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The design required that the entire
site that was to be treated by in situ
solidification first be excavated to a
depth of 4 ft, corresponding to local
frost depth. This excavated area was
subsequently backfilled with clean soil,
protecting the top of the monolith from
degradation by freeze-thaw action.