Environmental Engineering Reference
In-Depth Information
Corrosivity
Because of their high acidity, organic materials are usually highly corrosive to steel and
concrete.
Mixtures
Sand and silt mixed with clay commonly assume the properties of clay soils to a degree
increasing with the increasing percentage of clay included in the mixture. The plasticity
chart (see
Figure 3.12)
relates PI and LL to the behavior of remolded clays, mixtures of
clays with sand and silt, and organic materials.
Engineering Properties Given in
Chapter 3
Hydraulic Properties
Drainage, capillarity and frost heaving characteristics:
Table 3.10
provides general rating crite-
ria.
Permeability
: Various relationships based on the coefficient of permeability
k
are given in
Tables 3.11
to
3.14
and
Figures 3.13
to
3.15.
Rupture Strength and other Properties
Cohesionless soils
: Relative density, dry density, void ratio, and strength as related to gra-
dation and
N
are given in
Table 3.36;
relationships between
N
and DR are given in
Table
3.23
and
Figure 3.59.
Cohesive soils
: Relationships among consistency, strength, saturated weight, and
N
are
given in
Table 3.37.
Correlations between
N
and
U
c
for cohesive soils of various plastici-
ties are given in
Figure 3.94.
Cohesive soils classified by geologic origin with properties
including density, natural moisture contents, plasticity indices, and strength parameters
are given in
Table 3.38.
Compacted Materials
: Maximum dry weight, optimum moisture content, compression
values, strength characteristics, permeability coefficient, and CBR value range for various
compacted materials are given in
Table 3.39.
Deformability
Typical ranges for the elastic properties of various materials are given in
Table 3.25.
Typical
pressure-void ratio curves for various clay soils are given in
Figure 3.81,
and
pressure-void ratio curves and relative density relationships for a ”coarse to fine sand, lit-
tle silt” are given in
Figure 3.85.
5.3.6
Classification and Description of Soils
General
Current classification systems provide the nomenclature to describe a soil specimen in
terms of gradation, plasticity, and organic content as determined visually or as based on
laboratory index tests. They do not provide the nomenclature to describe mineral type,
grain shape, stratification, or fabric.
A complete description of each soil stratum is necessary for providing a basis for antic-
ipating engineering properties, for the selection of representative samples for laboratory
testing or for determining representative conditions for
in situ
testing, as well as for the
correlation of test results with data from previous studies.
