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

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