Ground Improvement through GROUTINGnitjsr.ac.in/course_assignment/CE10CE- 4230Grouting...Compaction grouting, also known as Low Mobility Grouting, is a grouting technique that displaces
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Ground Improvement
through
GROUTING
Department of Civil Engineering,
NIT, Jamshedpur
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Grouting & Types
of Grouts
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Grouting1. Grouting is the process to inject grout into the ground. Hence, the
volume of the ground ready to accept grout is the primary consideration
before any other considerations.
2. GROUT can be defined as a solution, an emulsion or suspension in water,
which will harden after a certain time interval. It can be divided into two
main groups:
a. Suspension Grout
b. Liquid Grout or Solution Grout.
3. Suspension grout is a mixture of one or several inert materials like
cement, clays etc. suspended in a fluid -- water. According to its dry
matter content it is either of the stable or unstable type. suspension grout
is a mixture of pure cement with water.
4. Liquid grout or solution grout consists of chemical products in a solution
or an emulsion form and their reagents. The most frequently used
products are sodium silicate and certain resins.
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GROUTING
1. Grouting is a process of ground improvement attained
by injecting fluid like material into subsurface soil or
rock.
2. Grouting is the injection
• specially formulated cement of stable suspensions or
• liquid into pores, fissures or voids, or
• the jetting of cement mixtures at
• high flow rate and pressure into the soil to create
soil- cement to increase the strength.
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Types of grout
• Numerous materials have been developed for use as
grouts.
• All have the property of fluidity, but this can be of
materials as diverse as thick pastes and mortars,
slurries, colloidal suspensions in water, emulsions of one
liquid in another, solutions, liquid resins and, even.
suspensions of very fine solids in gases.
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Types of grout1. Mortars and pastes (usually a combination of cementitious material and
filler)
2. Cement slurries and suspensions in water
3. Cement-bentonite suspensions in water
4. Bentonite (or other clay) colloidal suspension in water
5. Microfine cement colloidal suspensions in water
6. Chemical solutions usually in water
7. Chemicals in a colloidal system that form gels
8. Resins, ie organic chemicals.
• The thicker grouts are used for void filling, jet grouting, compaction
and squeeze grouting.
• The intermediate and colloidal suspensions are often used for
hydro-fracture.
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ADMIXTURES for Cement Grouting
Common admixtures used with cement grouts:
1. Calcium chloride ]
2. Sodium hydroxide ]---for accelerating setting time
3. Sodium silicate
4. Gypsum
5. Lime sugar
6. Sodium tannate
7. Fine bentonite
8. Clay
]
]
]---for retarding setting time.
]
]
]
9. Ground shale
10. Rock flour
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]---for reducing cost of grout & reduces
] strength of grout
The assessment of
groutability
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The assessment of groutability
• Grouting, for whatever purpose, affects the void spaces of the
ground either to fill them or to reduce their volume.
• The groutability of the ground is not a single or fixed characteristic,
but depends on the
• purpose of the grouting,
• the technique and the grout, as well as,
• the nature of the ground and its voids.
• Different techniques or combinations of techniques with different
grouts can achieve the same purpose. Very broadly, however, the
grouting processes associated with different types of ground are
shown in Table next.3/27/2020
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What grouting does?
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Why grouting is required?
• There are nine main reasons for using grouting as the means of
ground improvement
1. Reducing the permeability of the ground.
2. Providing a barrier or cut-off to water flow in the ground.
3. Increasing the strength of the ground to permit its safe excavation.
4. Increasing the strength, stiffness and bearing capacity of the ground.
5. Increasing the overall density of the ground.
6. Infilling natural cavities.
7. Infilling mineral workings.
8. Infilling voids adjacent to structures.
9. Compensating for ground loss caused by adjacent works.
• The above list shows the versatility of grouting techniques, made
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List of few applications of grouting in Civil Engineering
1. FILLING VOIDS TO PREVENT EXCESSIVE SETTLEMENT
2. TO INCREASE ALLOWABLE PRESSURE OF THE SOIL BOTH FOR NEW STRUCTURES AND / OR
ADDITIONS TO EXISTING STRUCTURES.
3. CONTROL OF GROUNDWATER FLOW
4. PREVENTION OF LOOSE - LOOSE TO MEDIUM SAND DENSIFICATION UNDER ADJACENT
STRUCTURES (I.E. BOTH FOR VERTICAL AND LATERAL MOVEMENTS) DUE TO ADJACENT
EXCAVATIONS, PILE DRIVING ETC.
5. GROUND MOVEMENT CONTROL DURING TUNNELING OPERATIONS
6. SOIL STRENGTHENING TO REDUCE LATERAL SUPPORT REQUIREMENT
7. SOIL STRENGTHENING TO INCREASE LATERAL AND VERTICAL RESISTANCE OF PILES.
8. STABILIZATION OF LOOSE SANDS AGAINST LIQUEFACTION
9. FOUNDATION UNDERPINNING
10. SLOPE STABILISATION
11. VOLUME CHANGE CONTROL OF EXPANSIVE SOILS THROUGH PRESSURE INJECTION OF
LIME SLURRY (ONLY FOR SOME EXPANSIVE SOILS NOT ALL)
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History of Grouting
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History of Grouting in Civil Engineering• Its traceable record can be as early as in the beginning of 1800s.
• In 1802, the idea of improving the bearing capacity under a sluice by the injection of
self-hardening cementitious slurry was first introduced
• In 1864, Peter Barlow patented a cylindrical one-piece tunnel shield which could fill
the annular void left by the tail of the shield with grout. It is the first recorded use
cementitious grout in underground construction.
• In 1893, the first systematic grouting of rock in the USA as performed at the New
Croton Dam, in New York.
• In 1960s, jet grouting technique was developed.
• In 1977, first application of compaction grouting for controlling ground movement
during construction of the Bolton Hill Tunnel.
• In 1995, the first industrial application of the compensation grouting concept was
conducted at the construction site of the Jubilee Line Extension Project in London.
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Few Visuals for
Grouting
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3
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Pile walls and grouting
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Safety can be
brought back by
grouting3/27/2020
Grouting to regain the
safety of the Foundation
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Grouting Process
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GROUTING PROCESSES
• Grouting methods be classified by process rather than
by grout material or end result. Accordingly Grouting
can be of types below.
1. Permeation grouting
2. Hydro-fracture grouting
3. jet grouting
4. Cavity infilling
5. Compaction, squeeze and compensation grouting
These main processes of Grouting are explained in the
sketches to be followed
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GROUTING PROCESSES - Contd.
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GROUTING PROCESSES - Contd.
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GROUTING PROCESSES - Contd.
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GROUTING PROCESSES - Contd.
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Grouting Explained through
Pictures and Videos
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Steps in Grouting
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Cement grouting, also known
as slurry grouting or high
mobility grouting, is a grouting
technique that fills pores in
granular soil or voids in rock or
soil, with flowable particulate
grouts.
Depending on the application,
Portland cement or microfine
cement, grout is injected
under pressure at strategic
locations either through single
port or multiple port pipes.
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Chemical grouting is a grouting
technique that transforms
granular soils into sandstone-like
masses, by permeation with a
low viscosity grout.
The soils best suited for this
technique are sands with low
fines content.
The grout permeates the soil
and solidifies it into a
sandstone-like mass. The
grouted soil has increased
strength and stiffness, and
reduced permeability.
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Compaction grouting, also
known as Low Mobility
Grouting, is a grouting
technique that displaces
and densifies loose granular
soils, reinforces fine grained
soils and stabilizes
subsurface voids or
sinkholes, by the staged
injection of low-slump, low
mobility aggregate grout.
The expansion of the low
mobility grout bulbs displaces
surrounding soils. When
performed in granular soil,
compaction grouting increases
the surrounding soils density,
friction angle and stiffness.
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Compensation
Grouting or
Fracture Grouting
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Fracture grouting, also
known as compensation
grouting, is a grouting
technique that hydro-
fractures in situ soil.
Once the hydro-fracture
pressure of the soil is
exceeded, fractures open
up in the soil and are
immediately expanded by
the subsequent influx of
grout.
The process results in
controlled heave of the
overlying soils and
structures. The technique
has been used to re-level
structures.
Jet grouting is a grouting
technique that creates
in situ geometries of
soilcrete (grouted soil).
The jets erode and mix
the in situ soil as the drill
stem and jet grout
monitor are rotated and
raised.
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Cavity infilling
grout
The grout is injected
under low pressure
through a predrilled
hole. The grout then
expands to fill the
crack or void.
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Typical equipment layout for grouting
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Thank You
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