Lesson 3/Learning Event 2
Learning Event 2
IDENTIFY THE STEPS IN A FIELD INVESTIGATION
Field investigation is done in three phases:
Investigation of existing information
The first step is site evaluation. The object of site evaluation is to determine the soil strata and mineral
composition of rocks and to try to foresee problems which may occur in construction or future
As described above in the section on hasty surveys, the soils engineer can obtain information from areas
which expose the substrata. The areas include:
highway and railroad cuts
existing shafts and tunnels.
The next step is to obtain existing information. There are many sources of information available to the
soils engineer. Using these to the fullest extent may help shorten the investigation. These sources will
be used mostly to locate small areas of a large general area which are suitable for further investigation.
For the final site selection, actual field investigations must be made.
Among the sources of information to be consulted in planning a soil survey are: intelligence reports,
local inhabitants, and aerial photographs.
INTELLIGENCE REPORTS AND LOCAL INHABITANTS
Intelligence Reports. Intelligence reports which include maps
and studies of soil conditions usually are
available for areas in which military operations have been planned. Among the best and most
comprehensive of these are the National Intelligence Surveys and Engineer Intelligence Studies. These
reports are a source of information on geology, topography, terrain conditions, climate and weather
conditions, and sources of construction materials.
Local Inhabitants. Local inhabitants may provide information to supplement intelligence reports or
provide information about areas for which intelligence reports are unavailable. Information obtained
from this source would include possible location of borrow material, sand and gravel deposits, and peat
or highly organic soils, and information on the climate and topography of the area.