2. 2INTRODUCTIONINTRODUCTION
• Tunnel Boring Machine (TBM) also known as ‘MOLE’.
• It is used to excavate tunnels with a circular cross section.
• It can bore through anything from hard rock to sand.
• Different types of TBMs are used for different
geotechnology.
• Used as an alternative to drilling and blasting (D&B)
methods and conventional 'hand mining' in soil
• Limits the disturbance to the surrounding ground and
produces a smooth tunnel wall.
• Suitable to use in heavily urbanized areas.
continues….
3. 3• TBMs is also a complete single unit moving factory
• Only little finishing work has to be done after using TBMs as
this single unit can do
DRILLING SYSTEMS
CONCREATE SPRAYING
SEGMENTAL LINING
ROCK SUPPORTING
PIPE JACKING
CONVEYANCE OF EXCAVATED
MATERIAL
4. 4GEOTECHNOLOGYGEOTECHNOLOGY
•The geological and hydraulic information about the soil forms
the basis for planning and executing tunneling and pipe
jacking projects.
• Provide the basic data for selecting tunneling methods
and cutting wheel tools that will cut through the native ground
efficiently and economically.
• The most important ground or rock-mechanical parameters for
designing a tunnel boring machine are:
-grading curve -rock/clay mineralogy
-ground water penetration -quality of the rock
-consistency limits -hardness of the rock
6. 6
CUTTING ROLLSCUTTING ROLLS
•Cutting rolls are used to tear of the
soil and rock from tunnel face.
•They are mounted on the cutting
heads.
•Different types of materials are used
for different ground condition.
•They are placed radially, so as to
have maximum efficiency.
•They can revolve themselves in full
360 degree.
•They can be replaced periodically.
•They presses the tunnel face with a
force of 26 tons.
7. 7
CUTTER HEADSCUTTER HEADS
•Cutter heads is the part of the
TBM which faces the ground
to be tunneled.
•It will revolve in speed of 1 to
10 rpm
•Cutting rolls and cutting
blades are mounted here.
•Cutter head can revolve 360
degree
•They are also provided with
openings called muck buckets
for extracting excavated
materials (chips) to the
conveyor.
8. GRIPPERGRIPPER 8
•Grippers are also called
supporting arms of TBMs.
•All TBMs have at least a pair of
grippers.
•Grippers provide a radial thrust
to the tunnel walls with the help
of hydraulic press.
•Grippers are used only when
cutter head moves forward
against the tunnel face.
9. 9CONVEYORSCONVEYORS
•The chips are carried out off
the tunnel from the tunnel face
via many methods,
-Mechanical transportation
Auger conveyor
Conveyor belts
Muck cars
-Hydraulic transportation
(slurry circuit)
Continues…….
10. 10CONVEYORSCONVEYORS
•This conveyor system travels in full length of the tunnel.
•Chips are then dumped on disposal plant.
•This keeps the workspace clean and easy to work
11. 11CONCRETE SPRAYER AND BLOCKSCONCRETE SPRAYER AND BLOCKS
•In steel arc segmenting, concrete
readymade blocks are placed in-
between each.
•While in meshing, concrete is
sprayed at high pressure by concrete
sprayers.
•The concrete sprayer is operated
automatically, so that it provide even
finishing everywhere.
•Concrete sprayers are fitted behind
the gripper section.
•Concrete blocks are placed
manually with help of machineries
only after the tunneling process is
finished.
12. 12PRESS FRAMESPRESS FRAMES
•Press frames are hydraulic piston cylinder arrangement.
•The cutter heads are moved forward due to the extension of
pistons.
•The processes stops when the cylinder piston reaches
maximum.
13. 13
MACHINE TECHNOLOGYMACHINE TECHNOLOGY
• For tunneling project different kind of TBMs are used.
• Type of TBM varies with ground condition.
• Soft ground type
- EPB technology
- Slurry shield
- Mix shield
• Hard ground type
- Single shield TBM
- Double shield TBM
14. 14EPB TechnologyEPB Technology
•EPB is used in soft ground type with less than 7 bar of pressure
•Uses combination of tungsten carbide cutting bits, carbide disc cutters, and/or
hard rock disc cutters.
•The EPB gets its name because it is capable of holding up soft ground by
maintaining a balance between earth and pressure.
• Also additives such as bentonite, polymers and foam are injected into the ground to
further stabilize it.
•Auger conveyor is used to remove chips.
15. 15
SLURRYSHIELD &MIXSHIELDSLURRYSHIELD &MIXSHIELD
•In soft ground with very high water pressure and large amounts of ground
water, Slurry Shield TBMs are needed.
•Offers a completely enclosed working environment.
•Soils are mixed with bentonite slurry, which must be removed from the
tunnel through a system of slurry tubes that exit the tunnel. Large slurry
separation plants are needed on the surface for this process, which
separate the dirt from the slurry so it can be recycled back into the tunnel.
•For recycling separation plants are used.
Continues………
17. 17
SINGLE SHIELD TBMSINGLE SHIELD TBM
•Single shield TBMs have no shield as that of in soft ground type.
•Excavation is done by cutter rolls transferred through openings in the cutter
head to a belt conveyor, and then to muck cars or conveyor belt.
•There is no excavation chambers as chips are of solid and not as slurry..
•More smoother tunnel walls can be created using single shield TBMs.
18. 18
DOUBLE SHIELD TBMsDOUBLE SHIELD TBMs
•These are the most technically sophisticated tunnel boring machines in
use.
•This type of machine is ideally suited for drilling long tunnels in hard rock
where geological fault zones occur.
•Its main feature is an extendable front shield in the front part of the
machine, which allows the cutter head to be extended.
19. Bertha (Tunnel Boring Machine)
o Bertha, also known as Big Bertha, is a 57-foot-diameter
(17.4 m) tunnel boring machine
o The biggest Tunnel Boring Machine on Earth
o Tunnel Boring Machine built specifically for the
Washington State Department of Transportation's
(WSDOT) Alaskan Way Viaduct replacement tunnel
project in Seattle.
o Weight : 7,000 tons
o Length : 325 feet
o Cost : $80,000,000
o Tunnel : 9,270 ft. (2,830 m) length
o Project Cost : $3.1 billion(estimated)
19
22. 22
EXTERNAL FEATURESEXTERNAL FEATURES
1) ADVANTAGES
-Is mainly suitable for urban tunneling.
-Less time for completion.
-Total expense is less than any other process.
-Less manual effort is needed.
-Risk factors like explosion, rock slide, etc are less.
2) DISADVANTAGES
-High initial expense.
-Difficult to transport machines.
-Need many skilled technicians.
23. 23
CONCLUSIONCONCLUSION
For a fast developing country like INDIA, it is very
important to have traffic free transport facilities, underground
water supply canal, etc. As these thinks have major part in
boosting our economics by foreign investments. The tough task is
that to have all this in highly dense metros like Delhi, Mumbai,
Bangalore, Chennai, etc. its not possible to build flyovers at all
places to as it leads to traffic conjunctions till the project finishes.
Also when it come to have transportation across hilly areas time
taken and risk factors are more.
To over come this and to provide safe and comfortable
transportation in all terrains TUNNELING is the best way to it
provide easy tunneling even under huge buildings, tough terrains,
under river beds too. It is the best suitable method for a fast
developing nation.
