2. INTRODUCTION
A tunnel is an underground passageway, completely
enclosed except for openings for egress, commonly at
each end.
A tunnel may be for road traffic,,canal,hydroelectric
station,sewer etc.
The Delaware Aqueduct in New York USA is the longest
tunnel, of any type, in the world at 137 km (85 mi)
3. REQUIRMENTS OF TUNNEL
IT IS VERY USEFUL WHERE BRIDGE FAIL TO FULFILL
REQUIRMENTS LIKE IN SEA ,IN URBAN AREA ,AND IN
MOUNTAINS.
EFFICIENT COPARED TO BRIDGES.
IN WAR TIME IT IS MUCH DIFFICULT TO DESTROY A TUNNEL
BUT DESTRUCTION OF BRIDGE IS TOO EASY.
LOTS OF LAND AND TIME IS SAVED.
4. TUNNEL BORING MACHINE
tunnel boring machine (TBM) is a machine used
to excavate tunnels with a circular cross section
through a variety of soil and rock strata
They can bore through anything from hard rock to
sand
Tunnel diameters can range from a metre to
19.25metre
5.
6. DRILL AND BLAST
1.Before the advent of tunnel boring
machines, drilling and blasting was
the only economical way of excavating
long tunnels through hard rock, where
digging is not possible.
2.Even today, the method is still used in
the construction of tunnels
But the disadvantage is it disturbance the
sorroundings
8. HISTORY
The first successful tunnelling shield was developed
by Sir Marc Isambard Brunel to excavate the Thames
Tunnel in 1825
In the United States, the first boring machine to have
been built was used in 1853 during the construction
of the Hoosac Tunnel.
10. WORKING OF TBM
A TBM is shaped like a tube. At the front is a rotating
disk with cutting teeth that can shear through rock
The pulverized rock falls to a conveyor belt that
carries it to the back of the TBM
Hydraulic feet grip the sides of the tunnel and push
the machine forward
There is also the ability to insert plates to line the
interior of the tunnel
12. ADVANTAGE
Higher advance rates
Continuous operations
Less rock damage
Less support requirements
Uniform muck characteristics
Greater worker safety
Potential for remote, automated operation.
13. DISADVANTAGE
The major disadvantage is the upfront cost
TBMs are expensive to construct, and can be difficult
to transport.
TBM can not move in backward direction
TBMs are expensive to construct, and can be difficult
to transport.
15. CONCLUSION
The main purpose for any organisation is that
provide safe environment for worker and TBM is
more control and safe than drilling and blasting