Lesson 3/Learning Event 1
Learning Event 1
IDENTIFY TYPES OF SOIL SURVEYS
The objective of the soil survey is to obtain information relating to the physical properties of the soil and
the arrangement of the underlying materials. A soil survey can determine the location, sequence,
thickness, and area extent of each soil stratum, including a description and classification of the soils and
their structure and stratification in the undisturbed state. Significant geologic features, such as
concretions, and mineral chemical constituents also are included in the data from exploration.
The investigation is conducted in the office, in the field, and in the laboratory. It begins with a
preliminary program which discloses general characteristics that will provide you with a broad
understanding of soil conditions and engineering problems which may be encountered, such as drainage,
slope stability, differential settlement, and equipment production rates, to name a few. The basic soils
information is invaluable when planning, conducting, and interpreting later detailed soil surveys.
The end product of the soils survey is an accurate engineering analysis of the subsurface conditions
which will enable you to render the safest, most economical design.
TYPES OF SOIL SURVEYS
A soil survey consists of gathering soil samples for examination, testing, and classifying soils, and
developing a soil profile. Two types of soil surveys are the hasty survey, which is made either under
expedient conditions or when time is very limited, and the deliberate survey, which is made when
adequate equipment and time are available.
Although this lesson describes the hasty survey, it is primarily concerned with the deliberate survey.
HASTY SURVEY
The hasty survey should be preceded by as careful a study of all available sources of information as
conditions permit. If possible, a trained person may observe soil conditions in the proposed construction
area from the air. Careful aerial observation gives an overall picture, which is often difficult to secure at
ground level because important features may be obscured in rough or wooded terrain. Rapid ground
observation along the proposed road location or at the proposed airfield site will also yield useful
information. Observation of the soil profile may be made along the natural banks of a stream, eroded
areas, bomb craters, and other exposed places. As construction proceeds, additional soil studies will
augment the basic data gained through the hasty survey and will dictate necessary modification in
location, design, and construction.
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