TM 5-818-4/AFM 88-5, Chap. 5
5-3. Postconstruction distress. Good backfill
tion can be made with the contractor and with the of-
construction practices and control will minimize the
fice or firm that will install the devices. Inspectors
potential for postconstruction distress. Nevertheless,
should inspect any instrumentation furnished and in-
the possibility of distress occurring is real, and meas-
stalled by the contractor. Records must be made of the
ures must be taken to correct any problems before they
exact locations and procedures used for installation
become so critical as to cause functional problems with
and initial observations. Inspectors should ensure that
the facility. Therefore, early detection of distress is es-
necessary extensions are added for the apparatus (such
sential. Some early signs of possible distress in-
as lead lines and piezometer tubes) installed within the
clude: settlement or swelling of the backfill around
backfill as the backfill is constructed to higher eleva-
the structure; sudden or gradual change of instrumen-
tions. Care must be used in placing and compacting
backfill around instruments that are installed within
tation data; development of cracks in structural walls;
and adverse seepage problems. Detailed construction
or through backfill. Where necessary to prevent
records are important for defining potential distress
damage to instruments, backfill must be placed
areas and assessing the mechanisms causing the
manually and compacted with small compaction equip-
distress.
ment such as rammers or vibratory plates.
6-5
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