Easy Way of Grouting Techniques in Underground Space

1. Grouting inTunnel to Improve
Rock and Soil Mass
Presented By:
OmVir Singh
Grouting Specialist
( Samsung C&T Saudi Arabia )
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2. Most effective Methods :
1. Grouting
2. Rock Bolting
3. Shotcrete / Guniting
4. Cable anchorage
IMPROVEMENT OF ROCK MASS
PROPERTIES

3. IMPROVEMENT OF ROCK MASS
Pre-
planned
Emergent
Condition

4. Grouting
Defined as the injection of a liquid of
variable viscosity under pressure into a
particular part of or parts of the earth’s
crust through specially constructed holes
to fill and seal voids, cracks, seams, fissures
etc.
Done for strengthening and/or water
sealing

5. Grouting
Grout is a construction
material used to fill voids, and
seal joints
Grout is generally composed
of a mixture of water, cement,
sand.
It is applied as a thick liquid
and hardens over time, much
like mortar.
Initially, its application
confines mainly in void filling,
water stopping and
consolidation. Nowadays, it
extends to tunnel excavation
works, to strengthen ground in
solving geotechnical problems.

6. Grain size of the grout
Grain size of the grouting fluid, such as cement slurry should be
smaller than the size of the pores of the mass to be grouted
For successful operation following criteria is used
D15 (Soil)/D85 (Grout) > 25 for Soil
D (fissure)/Dmax (Grout) > 3 for Rock

7. Types of Grouting
GROUT can be applied 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:
1. Suspension Grout
Suspension grout is a mixture of one or several inert materials like
cement, clays etc. suspended in a fluid -- water.
2. Liquid Grout or Solution
Grout.
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.

8. TYPES OF GROUTS
Cement-based grouts are the most frequently used in
both water stopping and strengthening treatment.
Chemical Grout : Suitable for finely fissured rock mass
Bituminous Grout: also known as emulsion grout,
includes bitumen because they form an emulsion when
mixed with water, bitumen grouts are sensitive to
temp, hence they may not be suitable at greater depth.

9. •Methods of Grouting
1. Stage Grout: done in stages, starting from nearest
discontinuity from surface to the deepest discontinuity
2. Packer Grout: holes are first drilled to deepest level to be
grouted.The process is repeated from bottom to top till
the whole section is grouted
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10. Compaction Grouting
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11. Rock Fissure Grouting
• Rock fissure grouting is the use of a hole drilled through the
fissures and joints of a rock mass to allow grout to be injected at
close centers vertically and re-injecting, if necessary.
• Grouting Mechanism
• The grout is injected under pressure through the grout hole
drilled into the rock mass to be treated.
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12. Rock Fissure Grouting
Main applications are:
1. Sealing rock mass underneath and at ends of dams to
prevent seepage or leaking of the reservoirs.
2. Sealing rock mass above and underneath a rock tunnel
to prevent water seepage into the excavated tunnel.
3. Cementing fractured rock mass.

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14. Rock Bolting
Done to reinforce and support
partially detached, thinly
laminated or unsuitable which
otherwise would be subjected to
failure.With rock bolting, the rock
is loaded in such a way that the
resistance to shear along the
planes of weakness is increased
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15. Mechanism of Rock Bolting
A number of holes are drilled in the rock at a
designated spacing, the length of holes are selected
such that they terminate in a sound rock in which the
bolt can be anchored properly and take up the loads.
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16. Rock Bolts
Steel bolts are frequently set in holes drilled into the rock to
assist in supporting the entire roof or individual rock slabs that
tend to fall into a tunnel.
Rock bolts maintain the stability of an opening by suspending
the dead weight of a slab from the rock above by providing a
normal stress on the rock surface to clamp discontinuities
together and develop beam action by preventing key blocks
becoming loosened so that the strength and integrity of the
rock mass is maintained.

17. Rock Bolting

18. • Guniting/ Shotcrete
Fluid mixture of fine sand, cement
and water applied through nozzle
ejecting at a high velocity, done
on the exposed surface for sealing
the surface cracks and protecting
the surface from weathering.

19. Shotcrete/Guniting
Shotcrete is best known in tunnelling and Slope Protection.
Mortar and concrete are increasingly being used for the support of
underground excavations.
A combination of rock bolts and shotcrete has proved an excellent temporary support for
all qualities of rock.
Quick-setting concrete is sprayed onto the bare rock surface
immediately after excavation, and rapidly hardens to form a
preliminary support until the final lining of conventional
poured concrete can be installed.

20. Cable Anchorage
Purpose is same as that of rock bolting.
The difference in cable anchorage and
rock bolting is that cables have length
much more than rock bolts. In rock
bolting system, individual rock bolts are
put into the rock at specified spacing. But
in cable anchorage system, a number of
wires in a group form a cable and the
cables are put into the rock mass at the
pre-determined positions, suitable in
case of anchoring a foundation subjected
to bouncy, especially under sea