06-07-2012, 01:03 PM
Soil Stabilization for Road sand Air fields
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Soil stabilization is the alteration of one or
more soil properties, by mechanical or chemical
means, to create an improved soil material
possessing the desired engineering properties.
Soils may be stabilized to increase
strength and durability or to prevent erosion
and dust generation. Regardless of the purpose
for stabilization, the desired result is the
creation of a soil material or soil system that
will remain in place under the design use conditions
for the design life of the project.
Engineers are responsible for selecting or
specifying the correct stabilizing method,
technique, and quantity of material required.
This chapter is aimed at helping to make the
correct decisions. Many of the procedures
outlined are not precise, but they will “get you
in the ball park.” Soils vary throughout the
world, and the engineering properties of soils
are equally variable. The key to success in
soil stabilization is soil testing. The method
of soil stabilization selected should be verified
in the laboratory before construction and
preferably before specifying or ordering
materials.
Methods of Stabilization
BASIC CONSIDERATIONS
Deciding to stabilize existing soil material
in the theater of operations requires an assessment
of the mission, enemy, terrain,
troops (and equipment), and time available
(METT-T).
Mission. What type of facility is to be
constructed—road, airfield, or building
foundation? How long will the
facility be used (design life)?
Enemy. Is the enemy interdicting
lines of communications? If so, how
will it impact on your ability to haul
stabilizing admixtures delivered to
your construction site?
Terrain, Assess the effect of terrain
on the project during the construction
phase and over the design life of the
facility. Is soil erosion likely? If so,
what impact will it have? Is there a
slope that is likely to become unstable?
Troops (and equipment). Do you have
or can you get equipment needed to
perform the stabilization operation?
Time available. Does the tactical situation
permit the time required to stabilize
the soil and allow the stabilized
soil to cure (if necessary)?
There are numerous methods by which
soils can be stabilized; however, all methods
fall into two broad categories. They are—
Mechanical stabilization.
Chemical admixture stabilization.
MECHANICAL STABILILIZATION
Mechanical stabilization produces by compaction
an interlocking of soil-aggregate
particles. The grading of the soil-aggregate
mixture must be such that a dense mass is
produced when it is compacted. Mechanical
stabilization can be accomplished by
uniformly mixing the material and then compacting
the mixture. As an alternative,
additional fines or aggregates maybe blended
before compaction to form a uniform, wellgraded,
dense soil-aggregate mixture after
compaction.
Limitations
Without minimizing the importance of
mechanical stabilization, the limitations of
this method should also be realized. The
principles of mechanical stabilization have
frequently been misused, particularly in
areas where frost action is a factor in the
design. For example, clay has been added to
“stabilize” soils, when in reality all that was
needed was adequate compaction to provide a
strong, easily drained base that would not be
susceptible to detrimental frost action. An
understanding of the densification that can
be achieved by modern compaction equipment
should prevent a mistake of this sort.