Learning Event 2 Identify the Steps in A Field Investigation

Soils Engineering
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Lesson 3/Learning Event 2

Learning Event 2

IDENTIFY THE STEPS IN A FIELD INVESTIGATION

Field investigation is done in three phases:

 Site evaluation

 Investigation of existing information

 Subsurface investigation.

SITE EVALUATION

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

expansion.

As described above in the section on hasty surveys, the soils engineer can obtain information from areas

which expose the substrata. The areas include:

 river banks

 escarpments

 highway and railroad cuts

 quarries

 existing shafts and tunnels.

EXISTING INFORMATION

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.