TM 5-818-1 / AFM 88-3, Chap. 7
CHAPTER 4
FIELD EXPLORATIONS
under consideration, including previous excavations,
4-1. Investigational
programs.
Field
material storage, and buildings. Use table 4-1 as a
investigations can be divided into two major phases, a
guide to sources and types of documentation.
surface examination and a subsurface exploration:
b. Field reconnaissance. A thorough visual
Surface Examination
Subsurface Exploration
examination of the site and the surrounding area by the
Documentary evidence
Preliminary
foundation engineer is essential. This activity may be
Field reconnaissance
Detailed
combined with a survey of local experience. The field
Local experience
reconnaissance should include an examination of the
following items as appropriate:
a. Documentary evidence. The logical and
(1) Existing cuts (either natural or man-
necessary first step of any field investigation is the
made). Railway and highway cuts, pipeline trenches, and
compilation of all pertinent information on geological and
soil conditions at and in the vicinity of the site or sites
Table 4-1. Types and Sources of Documentary Evidence
Types
Sources
Descriptions
Topographic, soil, drift
Local, state, Federal, and uni-
These maps provide information on lay
(overburden), and bedrock
versity geologic and agricul-
of land, faulting (tectonics), and
maps
tural organizations
material types
Surface and subsurface
U. S. Bureau of Mines and State
Such data help locate subsurface
mining data, present and
mining groups
shafts and surface pits. The pres-
past
ence of cavities in the foundation
must be known. Current and even old
workings may represent material
sources for construction. In addi-
tion, surface pits near site may pro-
vide opportunity to observe stratifi-
cation of foundation and allow taking
of disturbed samples
Aerial photographs, Conti-
U. S. Government Printing Office
Aerial photos offer a valuable means of
ental U. S.
establishing some insight into the
nature of foundation soils (2) and
also expedite familiarization with
the lay of the land
Aerial photographs, county
U. S. Soil Conservation Service,
and state areas
local or district office
Local experience
Technical Journals and published
May include considerable boring data,
reports; professional soci-
test data, and descriptions of
eties, universities, and state
problems in construction
agencies
Boring logs, water-well
State Building Commission, City
Some of these types of information can
records, and construction
Hall, County Court House, pri-
usually be obtained for existing
records
vate concerns
public buildings and facilities.
Private firms may cooperate in pro-
viding limited data
Hydrological and tidal data
State agencies, river boards,
Flood history, groundwater levels, and
U. S. Coast and Geodetic Sur-
tidal data indicate protective meas-
vey, and National Weather
ures required during and after con-
]Service
struction.Any groundwater informa-
tion may aid in dewatering facilities
and safe excavation slopes
U. S. Army Corps of Engineers
4-1
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