3.3.2
Excavation
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NOTE: For large excavations, more than one
excavation log may be required.
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Areas of contamination shall be excavated to the depth and extent shown on
the drawings and not more than [0.2] [_____] feet [60] [_____] mm beyond
the depth and extent shown on the drawings unless directed by the
Contracting Officer. Excavation shall be performed in a manner that will
limit spills and the potential for contaminated material to be mixed with
uncontaminated material. An excavation log describing visible signs of
contamination encountered shall be maintained for each area of excavation.
Excavation logs shall be prepared in accordance with ASTM D 5434.
3.3.3
Shoring
If workers must enter the excavation, it shall be evaluated, shored, sloped
or braced as required by EM 385-1-1 and 29 CFR 1926 section 650.
3.3.4
Dewatering
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NOTE: Dewatering can significantly increase the
cost of a project involving the excavation of
contaminated material and should be carefully
considered during design. TM 5-818-5 Dewatering and
Groundwater Control provides guidance on the design
of dewatering systems.
If water from dewatering operations will be allowed
to discharge on or into the ground, an NPDES permit
for dewatering is required. Reference the permits
paragraph of Section 01355 ENVIRONMENTAL PROTECTION
for permit requirements.
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Surface water shall be diverted to prevent entry into the excavation.
[Dewatering shall be limited to that necessary to assure adequate access, a
safe excavation, prevent the spread of contamination, and to ensure that
compaction requirements can be met.] [No dewatering shall be performed
without prior approval of the Contracting Officer.]
3.4
CONFIRMATION SAMPLING AND ANALYSIS
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NOTE: Confirmation samples and analyses are used to
verify cleanup criteria have been met. These test
results should be of relatively high quality. For
this reason, the designer should consider the
regulatory requirements, the complexity of the
monitoring needed, and quantitative Data Quality
Objectives in determining the analytical methods
specified.
The number of confirmation samples must be based on
the size of the excavation and regulatory
requirements. For small excavations, a minimum of
SECTION 02111
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