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1. MODERNINSITUTEOF ENGINEERING& TECHNOLOGY
Under
MAULANA ABUL KALAM AZAD UNIVERSITY OF
TECHNOLOGY
KOLKATA, WEST BENGAL-700064
PROJECT SUPERVISED BY ‘ MD HIRAN MIA ’ Sir
NAME :- DOLAN GHOSH
REG. NO :- 222690120059 OF 2022-23
ROLL NO :- 26901322012
TOPIC :- GROUND IMPROVEMENT TECHNIQUES .
DEPARTMENT :- CIVIL ENGINEERING
YEAR :- 3RD, SEMESTER- 6TH
SUBJECT :- FOUNDATION ENGINEERING
SUBJECT CODE :- CE(PE)601B

2. FOUNDATION ENGINEERING
PRESENT BY
DOLAN GHOSH

4. INTRODUCTION :-
The social, economic, cultural and industrial growth of any country depends heavily on its
transportation system. The only mode which could give maximum service to one and all is
transportation by highways and railways. As a result of development of infrastructures like
buildings, highways, railways and other structures in recent past years has resulted in scarcity
of good quality of land for construction projects. Therefore the engineers are bound to adopt
inferior and weak soil for construction. In present scenario the role of ground improvement
techniques has become an important and crucial task for various construction projects. By
ground improvement techniques the strength of the soil increases, its compressibility reduces
and the performance under applied loading enhances. The expansive and collapsible soils are
challenges to engineers due to their peculiar behavior of high swelling and shrinkage action.
The construction of foundation on sanitary landfills, soft soils, organic soils and karst deposits
are troublesome. It is to better to replace or bypass such type of soil strata by adopting suitable
design of foundation and if not possible the ground improvement is the best solution for a such
construction project site. This paper presents thorough study on various available modern
ground improvement techniques and their applications in civil engineering in present scenario.

6. 6
 NEED FOR GROUND IMPROVEMENT :-
1) Abandoning the site and locate the structure elsewhere.
2) Designing deep foundation to carry the weight of the structure.
3) Redesigning the structure according to the ground conditions.
Improve the properties of the ground prior to construction.
 WHAT IS GROUND IMPROVEMENT?
Ground Improvement is the modification of the ground properties in order to achieve the
required ground conditions for the particular use of ground. The areas of usage include a broad
construction spectrum from industrial, commercial and housing projects to construction of
dams, tunnels, ports, roadways and embankments. These techniques can be used for varied
types of soils ranging from coarse grained to fine grained.

7. GROUND IMPROVEMENT TECHNIQUES:-
Help
to reduce permeability
to reduce compressibility
to increase shear strength
to increase bearing capacity
METHODS OF SOIL IMPROVEMENT :-
Vibro-Compaction
Grouting
Vertical Drain
Dynamic Compaction
Stabilisation using Admixtures
Soil Nailing
Stone Columns

8. VIBRO COMPACTION :-
Vibro compaction densifies clean,cohesion less granular soils by means of a down hole vibrator
which is typically suspended from a crane and lowered vertically into the soil under its own
weight.
Penetration is usually aided by water jets integrated into the vibrator assembly. After reaching
the bottom of the treatment zone, the soils are densified in lifts as the probe is extracted.
During vibro compaction, clean sand backfill is typically added at the ground surface to
compensate for the reduction in soil volume resulting from the densification process.
The vibratory energy reduces the inter-granular forces between the soil particles,allowing them
to move into a denser configuration, typically achieving a relative density of 70 to 85 percent .
The treated soils have increased density, friction angle and stiffness.

9. GROUTING
Defined as the injection of a special liquid or
slurry material called ‘grout’ into the ground for
the purpose of improving the soil or rock.
Types of grouts:
a) Cement Grouts
b) Chemical Grouts

10. Grouting Methods
Intrusion grouting:-
 Consists of filling joints or fractures with grout.
 Helps in reduction of hydraulic conductivity.
 Used to prepare foundation and abutments for dams.
 Done using cement grouts.
Permeation grouting:-
 Injection of thin grouts into the soil.
 Once the soil cures, becomes a solid mass.
 Done using chemical grouts.
 Used for creating groundwater barriers or preparing
ground before tunneling.

11. Grouting Methods
Compaction grouting:-
When low-slump compaction grout is injected into granular
soils, grout bulbs are formed that displace and densify the
surrounding loose soils.
Used to repair structures that have excessive settlement
Jet grouting:-
Uses a special pipe with horizontal jets that inject grout into the
ground at high pressures.
Commonly used for ground water control projects.
Suitable for stabilizing soils before excavation or tunneling.

12. DYNAMIC COMPACTION:-
• Uses a special crane to lift 2-50 tons to heights of
7m-35m and then drop these weights onto the
ground.
• Cost effective method of densifying loose sands and
silty soils up to 15 to 30 feet deep.
• Good densification occurs up to a depth of 5m-10m.
VERTICAL DRAINS:-
Vertical drains are installed under a surcharge load to
accelerate the drainage of impervious soils and thus
speed up consolidation.
These drains provide a shorter path for the water to
flow through to get away from the soil.
Time to drain clay layers can be reduced from years to
a couple of months.

13. Consolidation takes place in
only one direction .
Vertical drainage path may
be substantially longer.
It may take more than 10
years to consolidate.
Pore water will flow
laterally.
Pore water pressure
dissipates as the layer drains
and water is conveyed
through vertical drains.
It takes only about 6 months
to consolidate.

16. Soil Nailing:-
This ground reinforcement process uses steel tendons
which are drilled and grouted into the soil to create a
composite mass. A shotcrete facing is typically
applied. Soil Nailing is an in situ technique for
reinforcing, stabilizing and retaining excavations and
deep cuts.
Procedure of soil nailing for soil slope is shown in
Fig-14. Soil nailing is not practical in-
Soft, plastic clays
Organics/Peat
Fills (rubble, cinder, ash, etc.)
This method was first implemented in 1972 for a
railroad widening project near Versailles in France.
This method is cost-effective and less time consuming
as compared to other conventional support methods.

17. It is a technique adopted for the soil which didn’t have
the sufficient characteristics to permit construction. The
stone column technique, also known as vibro-
replacement or vibro-displacement, is a ground
improvement process where vertical columns of
compacted aggregate are formed through the soils to be
improved. Stone columns, also known as granular piles,
consist of stone aggregates compacted into a vertical
hole. Generally, the size of aggregate used is 20mm to
75mm and the depth of hole is about 15m to 20m with
the diameter of 0.6m to 1.0m. The compaction is
achieved by a vibrating probe or by ramming.
STONE COLUMNS:-

18. INSTALLATION

19. ADVANTAGES OF
VERTICAL DRAINS:-
Minimum disturbance to soil layer
during installation.
High water discharge capacity.
High tensile strength prevents the
collapse of flow path.
Fast and easy installation up to 40 m.

20. Stabilization Using Admixtures
Most common admixture is Portland Cement.
When mixed with soil, forms soil-cement which
is comparable to a weak concrete.
Other admixtures include lime and asphalt.
Objective is to provide artificial cementation, thus
increasing strength and reducing both
compressibility and hydraulic conductivity.
Used to reduce expansion potential of clays.
Used in surface mixing applications.

21. CONCLUSION:-
Ground improvement is a rapidly developing field as suitable sites for construction are not
available these days.
Its applicability has been proven in the recent past for a wide range of structures such
as roads, runways, ports, power plants, railways, dams & other infrastructure facilities
.
These techniques have been used all over the world for a wide range of soils
starting from loose sands, silts, marine clays to weak rocks.
Based on the soil conditions, loading intensity and intended performance, an
appropriate ground improvement technique can be designed to attain the desired
performance.

22. REFFERENCES:-
AASHTO (American Association of State Highway and Transportation
Officials) (2003). Major Types of Transportation Construction
Specifications: A Guideline to Understanding Their
Evolution and Application. A report of the AASHTO Highway
Subcommittee on Construction Quality Construction Task Force,
Washigton, DC.
Alexiew, D., Horgan, G.J., and Brokemper, D. (2003). “Geotextile
encased columns (GEC): Load capacity and geotextile
selection.” In Foundations: Innovations, Observations, Design
and Practice. Thomas Telford, London.
Borel, S. (2007). Soil mixing innovations: Geomix, SpringSol and
Trenchmix. Presentation at Joint BGA/CFMS Meeting, London.
Bruce, D.A. (2012). “Computer monitoring in the grouting industry.”