TM 5-852-4/AFM 88-19, Chap. 4
U. S. Army Corps of Engineers
Figure 3-1. Required extent of explorations for large structure.
condition is common in the upper layers of soil during the
applicable will provide a reliable picture of the natural
thaw season so long as the underlying layer is frozen
subsurface conditions existing at a specific site and will
impervious soil. Normally, borings must be cased
provide a solid base of information for consideration of
through this saturated thawed layer. It is frequently
design options and performance of most design
found that explorations are most easily carried out during
analyses. Additional special technical data development
the colder part of the year, when water areas and the
may be required, depending on the specific type of
annual frost zone are solidly frozen, rather than during
foundation design to be explored. This may involve
the summer.
either laboratory or field tests, or both. Field tests must
c. Special
investigations.
Special
normally be performed at the naturally occurring field
ground temperatures; if the tests cannot be performed at
investigations may be necessary for unusual projects; for
the critical design temperatures because of time or other
example, the installation of a nuclear power plant may
requirements, the results must be adjusted or
require installation of temperature sensing equipment on
extrapolated
to
these
temperature
conditions.
a mush more elaborate scale than for an ordinary
Laboratory tests may be performed at coldroom or test
structure. Again, for structures in which the dynamic
chamber temperatures which are representative
response of the foundation is important, measurements
concontrolling field conditions and also permit
may be required of dynamic modulus and wave
economical investigation of the effects of full ranges of
propagation velocities in the field and in the laboratory.
conditions. If the general site conditions have become
In other cases creep deformation of electrical properties
clearly established in previous design studies at the
of the foundation (such as for grounding of antennas)
particular location, foundation studies for subsequent
may be critical. Installation of test piles may be required
facilities construction may often be less extensive and
during the site investigation or early construction phases
may in fact sometimes consist mainly of verification
in order to determine optimum methods of installation
explorations. General information requirements for site
and the actual allowable loadings and performance of
selection and development have been outlined in
piles.
Sometimes other field experiments may be
preceding paragraphs and are given in detail in TM 5-
required in order to determine if new or untried
11
.
The following
852-2/AFM 88-19, Chapter 2
construction methods are feasible under the particular
discussion is limited to specialized
soil and temperature conditions.
3-4. Site technical data. Careful collection of data as
outlined in the following paragraphs of this Chapter as
3-3
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