TM 5-852-4/AFM 88-19, Chap. 4
U. S. Army Corps of Engineers
Figure 4-69. Frozen soil column - diagrams of temperature and stress distribution.
Creep settlement deformations are computed using the
type of foundation. Of course, the revised design will
stress and temperature distributions shown in figure 4-
require repetition of the settlement computations.
69. The height of the column of soil to be analyzed is
4-8. Piling.
determined by the stress and temperature distributions.
a. General. Piling offers many advantages
The height of the column is assumed to extend to a
where construction is on frost-susceptible foundation
depth where the magnitude of the stress is so small that
soils in areas of deep seasonal frost penetration or
the contribution to creep deformation below this point
permafrost with high ice content''. Pile foundations can
can be neglected. The cross-sectional area of the soil
be constructed with minimum disturbance to the thermal
column is taken as the load area (i.e., the area of the
regime and can isolate the structure from the seasonal
footing). The column of soil used in the settlement
heave and subsidence movements of the annual frost
estimate is shown in figure 4-69.
The computed
zone and from at least limited degradation of the
temperature distribution from table 4-7 and the computed
permafrost. The structure load is transferred by the pile
stress distribution below the center of the foundation
to depths where soil supporting strength remains
from table 4-9 are shown as smooth curves in figure 4-
relatively stable through the life of the structure. General
69.
The rectangular shaded areas represent the
information on engineering and design of pile structures
20
approximate stress and temperature distributions used in
and foundations is contained in EM 1110-2-29062 and
5
the settlement computations. Table 4-10 shows the
TM 5-818-1/AFM 88-3, Chapter 7 , and the references
detailed computations for the settlements at the center
cited therein.
and at the corner of the foundation at the end of 25
b. Pile types. Pile materials may be timber,
years, assuming it is flexible.
If this differential
concrete, or steel. Composite piles may be profitably
settlement is not tolerable it will be necessary to increase
used to pro
the area of the footing or change the configuration or
4-109
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