TM 5-852-1/AFR 88-19, Volume 1
These alternatives are discussed in TM 5-852-4/AFM 88-
88-19, Volume 5. Connections of utilities to buildings are
19, Chap. 4.
discussed in TM 5-852-4/AFM 88-19, Chap. 4.
b. For areas of deep frost penetration without
permafrost, design options for stable foundations for
5-6.
Drainage and groundwater
subsurface conditions adversely affected by freeze and
a. Although annual precipitation intensity rates
thaw are similar to those in seasonal frost areas of the
are relatively light in much of the Arctic and Subarctic,
temperate zone, namely:
except in regions near coasts, the frozen condition of the
-Support foundation below the annual frost zone,
ground during much of year makes it necessary to
with protection as needed against uplift acting in
assume that the rate of infiltration in the Arctic, for
tangential adfreeze shear and against frost overturning
surface drainage design, is zero. A frequent cause of
or sliding produced by frost thrust.
damaging floods in these regions is the temporary
-Support structure on a compacted non-frost
damming of rivers by ice jams: however, floods caused
susceptible fill capable of adequately limiting freeze and
by heavy precipitation are not unknown, the Fairbanks,
thaw effects.
Alaska, flood of 1967 being an example.
-Employ thermal insulation, foundation loading,
b. Egress of groundwater may result in icing,
foundation soil replacement, heat or combinations of
which is undesirable near buildings or other structures.
these.
Icing caused by groundwater may be a serious problem
c. Detailed criteria and guidance for design of
when it interferes with road travel or drainage. Ground
foundations for structures, including basic considera-
icing effects can ordinarily be circumvented by inducing
tions, site investigations for foundations, construction
the icing at a place where it will do no harm. Drainage
considerations and monitoring of performance, are
structures like culverts should be constructed so that
presented in TM 5-852-4/AFM 88-19, Chap. 4.
they can be readily opened or kept open by steam
thawing or other methods.
5-5.
Utilities
c. The flow of water, both surface and
Utilities include water supply, sewerage, fire protection,
subsurface, is an important source of heat in permafrost
central heating, fuel, electrical and communication
thawing, particularly when the flow is concentrated in
systems. Many elements of these systems, such as
channels. In subarctic regions such channels, once
electric generators and water treatment mechanical
formed, may continue to thaw and deepen year after
equipment, are standard items that require no mod-
year.
In finegrained soils containing excess ice,
ification for use in the Arctic and Subarctic. However,
progressive differential settlement may result. Thaw of
other items may require special approaches.
For
ice and frozen fine-grained soil in fractures and fissures
example, water distribution pipes in the Arctic are
of bedrock may cause open joints or cavities (sink
commonly placed in insulated above-ground utilitdors or,
holes). The possibility of subsurface groundwater during
if the soil conditions permit laying pipes directly in the
construction should be considered in project planning.
ground, the water is heated before it enters the system
Concentrated drainage flow or discharge near structures
and it may be continuously recirculated. Con-sideration
that are built over fine-grained foundation soils should be
should be given, whenever possible, to use of heat
eliminated or diverted. Lake levels must not be allowed
recovery systems to conserve energy. Utility poles must
to rise if they might induce detrimental subsurface flow of
be protected against being pushed out of the ground by
warm surface water. It may be possible to exert some
frost heave when they are placed in frost-susceptible
control over the directions of summer drainage flow in
soil. This can be done by anchoring them firmly in
the active layer by modifying surface conditions so as to
permafrost or by supporting them above ground in rock-
selectively control depth of thaw. Even the most minor
filled cribs. Fuel storage tanks supported over thaw-
leaks from water, sewer or steam pipes can seriously
unstable permafrost require ventilated foundations to
degrade permafrost and must be prevented. Drainage
prevent thaw-settlement if they will contain fuel at above-
ditches cut into ice-rich permafrost should be avoided.
freezing temperatures. Sewage treatment facilities must
Subsurface drains are usually not practical in the Arctic
be designed to be safe from frost heave or thaw-
and Subarctic. When wells drilled through permafrost
settlement damage to pipes, tanks and other structural
encounter water under artesian pressure, great care is
elements; possible adverse effects of low temperatures
necessary to avoid loss of control of the well by thawing
on treatment processes must also be taken carefully into
and piping in thaw-unstable soil around the casing.
d. TM 5-852-7/AFM 88-19, Chap. 7 provides
account. Insulation on wires and electrical equipment
exposed to outdoor temperatures, which may drop to
criteria and guidance for surface drainage design and for
close to -70F, must not become brittle and crack under
control of icing in arctic and subarctic regions.
such conditions. Criteria and guidance for utilities in the
Arctic and Subarctic are presented in TM 5-852-5/AFR
5-3
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