1. Underwater tunnels are transport routes that are partly or wholly constructed under bodies of water, with different types including soft ground tunnels dug below the ocean bed, immersed tunnels made on the ocean floor, and floating submerged tunnels that float due to attached tethers. 2. Constructing underwater tunnels presents significant engineering challenges due to the tremendous water pressure from above and squeezing pressure from soft ground. Different tunnel construction methods are used depending on the material and conditions. 3. A proposed transatlantic underwater tunnel would connect North America and Europe, but presents massive challenges including the scales of resources, time, and extreme working conditions required that make completion effectively impossible with current technology.

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2. 8/5/2013Underwater tunnels 2
MBA(tech.)-Manufacturing
Chirag Chauhan #303
Ishan Parekh #315
Ankit Shah #317

3.  Paths of transport which are partly or wholly
constructed under a body of water
 A few of the prominent undersea tunnels are:
Sydney HarbourTunnel
SeikanTunnel
Cross-HarbourTunnel
ChannelTunnel
Eiksundtunnelen
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4. Soft GroundTunnel
• Tunnels which are dug up below the ocean bed
ImmersedTunnel
• Tunnels which are made on the ocean floor
Floating SubmergedTunnel
• Tunnels which are submerged & floating due to
tethers attached
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5. The heavy, wet ground pushes the tunnel
on all sides plus the additional pressure
which acts from above.
Water pushes from above tunnel, while
the tunnel's walls are squeezed by the
soft ground.
Water exerts tremendous pressure on all
sides of the tunnel, specially from up
above.
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Outer Shell made up of STAINLESS STEEL
Next comes up a thick layer of SUPERBUOYANT FOAM
Then follows up another hub of STAINLESS STEEL
Then comes the main structure whose frame is designed
using STAINLESS STEEL which is packed with
CONCRETE
Underwater viewing if needed is made up with ACRYLIC
PANELS

7.  A specific challenge or problem like a roadway or
railway, bodies of water, mountains or other
transportation routes.
 Depends heavily on the material through which it must
pass.
 Planning is so important to a successful tunnel project.
 Some of the factors which are considered:
Soil and rock types
Weak beds and zones, including faults and shear zones
Groundwater, including flow pattern and pressure
Special hazards, such as heat, gas and fault lines,
ventilations
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8. Different
Tools
Traditional
Fire Setting HandTools Explosives
Modern
Tunnel Boring
Machine
Compressed
Water Drills
Section Pre-
Construction
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Soft Rock
Tunnels TBMs
Immersed
Tunnels
Cut &
Cover
Immersed
Tube
Floating
Submerged
Tunnels
Partly
Immersed
Tethering

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Dredging a trench in the
riverbed or ocean floor.
Long, prefabricated tube
sections, made of steel
or concrete and sealed
to keep out water
Divers connect the
sections and remove the
seals

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The Chunnel connecting England
& France is a type of soft ground
tunnel.
Unless the tunnel is short, control
of the environment is essential to
provide safe working conditions
and to ensure the safety of
passengers after the tunnel is
operational. The solution was to
add two additional layers above
and below the main traffic tunnel.
The upper layer clears exhaust
fumes, while the lower layer
pumps in fresh air.

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Floats in water
Supported by its buoyancy
Tube is placed underwater,
deep enough to avoid
water traffic and weather,
But not so deep that high
water pressure needs to
be dealt with
Cables either anchored to
the Earth or to pontoons at
the surface prevent it from
floating to the surface

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Based on well-known
technology applied to floating
bridges & offshore structures
The construction is mostly
similar to that of immersed
tunnels
A submerged floating tunnel
must be anchored to the
ground or to the water
surface to keep it in place

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A version of the cut and cover
technique, is a cheap and easy
way to construct a tunnel under
water.
Dredging machines cut a trench
in the riverbed.
Preassembled, watertight tubes
are floated out and lowered into
place over the trench.
Segments are sealed together to
form the complete tunnel.
Then covered with a steel-and-
concrete casing to prevent the
tunnel from floating and to
protect it from damage caused
by passing ships.

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• the most massive project to be ever
undertaken
• global resources on an unimaginable
scale
– total steel equivalent to the total output of all the steel mills of the
world for more than a year i.e. 1 billion tonnes of steel
–Staggering cost of over $12 trillion
• unacceptable time to complete
– will take over a century or more to complete
–Some of the most extreme working conditions
But, if completed, it would change people’s life
like never before.

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 Soft ground – immense pressure of about 800
times of that on the surface
 Immersed – mid Atlantic ridge and the
seismic region
 Floating submerged – concept already used
in submarines

18. Lets take a look at the design of the
Transatlantic UnderwaterTunnel.
The Ingenious Design:
Click Here to view the design:
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19. Problems Solutions / Alternatives
Unimaginable Speed
• Friction
• Air Resistance
G – Force
Fires
Collisions
Abt 5000 miles/hr
• Maglev
• VacuumTubes
Controlled Gradual Accln.
Pivoting Rotating Suits
Massive Fire Suppression Systems
SlackenedTethers, Concrete & Steel
Walls, Unimaginable Speeds
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It seems to be our collective destiny to convert today’s impossibilities
into tomorrow’s realities.

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