The document discusses various ground improvement techniques used to modify the engineering properties of soils, including densification, consolidation, reinforcement, and chemical treatment. It provides details on specific techniques like vibroflotation, ground freezing, and soil nailing. Geosynthetics are also introduced as natural or artificial products used in geotechnical constructions to improve properties of soils.

1. Presentation by:
Aditya kumar
(0801ce17me01)
M.E in structures (2nd sem)

3.  Mechanical
properties are not
adequate.
 Swelling & shrinkage
 Collapsible soils
 Soft soils
 Organic and peaty
soils
 Sand and gravelly
deposits

4.  Ground improvement refers to a technique
that improves the engineering properties of
the soil mass treated.
 Usually the properties that are modified are:
Shear strength,stiffness & permeability.
 Ground improvement techniques are different
for different soil types

5.  Densification
 Consolidation
 Weight Reduction
 Reinforcement
 Chemical Treatment

6. Vibroflotation is a
technique
for in situ
densification of
thick layers of loose
granular
soil deposits.

10. FUNCTIONS AND USES
1. To increase the bearing
capacity
2. Improves the stiffness of
subsoil to decrease
settlements
3. To carry very high loads
4. More economical than
piling
5. No waiting period after
installation
6. homogenizes variable soil
properties
Example-Palm island (Dubai)

13.  Ground freezing is used for
groundwater cut-off, for earth
support, for temporary
underpinning, for stabilization
of earth for tunnel excavation,
to arrest landslides and to
stabilize abandoned
mineshafts.
 Typically, a row of freeze pipes
are placed vertically in the soil,
and heat energy is removed
through them, in a process
remarkably analogous to
pumping ground water from
wells.

14.  The design of a frozen earth
barrier is governed by the thermal
properties of the underlying soils
and related response to the
freezing system.
 When soft clay is cooled to the
freezing point, some portion of its
pore water begins to freeze and
clay begins to stiffen. If the
temperature is further reduced,
more of the pore water freezes and
the strength of the clay markedly
increases and also makes the soil
impervious.
 A temperature of +20 °F may be
adequate in sands, whereas
temperatures as low as –20 °F may
be required in soft clay.

15. Soil nailing is an
Insitu soil reinforcement technique used
for enhancing the stability of slopes,
retaining walls and excavations. The
technique involves installation of closely
spaced, relatively slender structural
elements, i.e., soil nails, into the ground
to stabilise the soil mass. These
reinforcing bars are installed into pre-
drilled holes and then grouted.
It has been alternative technique to
other conventional supporting system
as it offers flexibility, rapid construction
& competitive cost.
The purpose is to increase the Tensile &
Shear Strength of the soil & Restrain its
displacements.

17. The following are typical merits of adopting the soil nailing technique
in respect of construction, cost and performance:
It is suitable for cramped sites with difficult access because the construction
plant required for soil nail installation is small and mobile.
 It can easily cope with site constraints and variations in ground conditions
encountered during construction, e.g., by adjusting the location and length of
the soil nails to suit the site conditions.
During construction, it causes less environmental impact than cutting back
and retaining wall construction as no major earthworks and tree felling are
needed.
There could be time and cost savings compared to conventional techniques of
cutting back and retaining wall construction which usually involve substantial
earthworks and temporary works.
It is less sensitive to undetected adverse geological features, and thus more
robust and reliable than unsupported cuts. In addition, it renders higher system
redundancy than unsupported cuts or anchored slopes due to the presence of a
large number of soil nails. (f) The failure mode of a soil-nailed system is likely
to be ductile, thus providing warning signs before failure.

18. What is geosynthetics?
 Natural or artificial
product that is used
along with soil in
geotechnical
constructions.
 Natural: coir, jute, hemp,
etc.
 Artificial: polymeric or
metallic
 Types of Geo-Materials
 (Geosynthetics family)
 1. Geotextile.
 2. Geogrid.
 3. Geonet.
 4. Geo Membrane
 5. GeoComposites
 6. Geofoam
 7. Geocell
 8. Geomat
 9. Geomesh
 10. Geopipe
 11.Geospacer

21.  www.google.com
 www.slideshare.net
 http://www.cedd.g
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 https://en.wikipedi
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