IDENTIFICATION ID CLASSIFICATION OF SOIL AND ROCK
1. SCOPE. This chapter presents criteria for soil and rock identification
and classification plus information on their physical engineering
properties. Common soils and rock are discussed as well as special
materials such as submarine soils and coral, saprolitic soils, lateritic
soils, expansive and collapsing soils, cavernous limestone, quick clay,
permafrost and hydraulically placed fills.
2. RELATED CRITERIA. For additional criteria on the classification and
identification of soil and rock, see the following sources:
Pavements............................................... NAVFAC DM-5.04
Airfield Pavement....................................... NAVFAC DM-21 Series
GEOLOGIC ORIGIN AND MODE OF OCCURRENCE.
a. Principal Soil Deposits. See Table 1 for principal soil deposits
grouped in terms of origin (e.g., residual, colluvial, etc.) and mode of
occurrence (e.g., fluvial, lacustrine, etc.).
b. Importance. A geologic description assists in correlating
experiences between several sites, and in a general sense, indicates the
pattern of strata to be expected prior to making a field investigation (test
borings, etc.). Soils with similar origin and mode of occurrence are
expected to have comparable if not similar engineering properties. For
quantitative foundation analysis, a geological description is inadequate and
more specific classification is required. For sources of information on the
physical geology of the United States, see Chapter 2. A study of references
on local geology should precede a major subsurface exploration program.
c. Soil Horizon. Soil horizons are present in all sedimentary soils
and transported soils subject to weathering. The A horizon contains the
maximum amount of organic matter; the underlying B horizon contains clays,
sesquioxides, and small amounts of organic matter. The C horizon is partly
weathered parent soil or rock and the D horizon is unaltered parent soil and
Change 1, September 1986