A-E)"; and Technical Memoranda (TM) 183-1, dated Nov
1941, Rev Dec 1941, "Investigation of Filter
Requirements for Underdrains"; and Technical
Memoranda (TM) 195-1, dated Oct 1942, "Field and
Laboratory Investigation of Design Criteria for
Drainage Wells", U. S. Waterways Experiment Station.
Because of the high potential for clogging by
migrating fines or chemical precipitate, filter
cloth should not be used to protect relief well
screens.
In adapting this specification to any project the
form and phraseology should be changed as necessary
to properly specify the work contemplated. Changes
should be made in the original form to the extent
required to adapt the guide specification to local
conditions. Work such as concrete for backfill,
painting of exposed metal surfaces and seeding of
construction areas will have to be specified in this
section when such sections cannot be referenced as a
part of the contract.
For projects on which subsurface information is not
sufficiently developed to permit detailed design of
each well, a section should be added to the
specifications requiring the drilling of a small
diameter pilot hole at the location of each well.
Pilot holes should be sampled and logged in
sufficient detail to define the gradation of
pervious zones and the depths between which screens
should be set. The specifications should require
that samples of pervious materials be taken at 750
mm (2.5 foot) intervals of depth. Grain-size
distribution tests should be performed to provide a
basis for the design of the filter pack and the
screen openings. Samples taken by fishtail drilling
and other wash boring methods will not be permitted.
Where the subsurface information previously
obtained is sufficient, pilot holes are not required.
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1.1
REFERENCES
**************************************************************************
NOTE: Issue (date) of references included in
project specifications need not be more current than
provided by the latest guide specification. Use of
SpecsIntact automated reference checking is
recommended for projects based on older guide
specifications.
**************************************************************************
The publications listed below form a part of this specification to the
extent referenced. The publications are referred to within the text by the
basic designation only.
ASME INTERNATIONAL (ASME)
ASME B1.20.1
(1983; R 2001) Pipe Threads, General
SECTION 02525A
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