MMBC 8_VTU_Barch Underground structures construction

Constructed beneath the surface of the earth, Utilized for variety of applications like:
• Railways
• Subways
• Highways
• Sewage
• Water Transport
• Material Storage
• Foundation-laying work with pipes, wells, earth, reinforcement
• Involve in the removal of soil or rocks masses from their locations for the
required purposes

1. Underground
Structures
DSCA, Bangalore8
th
Semester-2022

2. Constructed beneath the surface of the earth, Utilized for variety of applications like:
•Railways
•Subways
•Highways
•Sewage
•Water Transport
•Material Storage
•Foundation-laying work with pipes, wells, earth, reinforcement
•Involve in the removal of soil or rocks masses from their locations for the
required purposes.

3. Sydney Opera house car parking
section

4. Gjøvik Mountain Sports Hall, Norway

5. Le Grand Louvre: I. M. Pei's Fusion
of Design and Technology

6. Various External Forces on the
Underground Structures
•It is expensive to build underground than to
build above ground.

•Mustbeabletowithstandthe
earth pressure forces.

•Protect the structure from ground water
intrusion.

7. Methods of Tunnel Construction

There are various types of construction techniques developed for construction
of
tunnels which are discussed below:

•Cut and cover method

•Bored tunnel method

•Immersed tube tunnel

•Clay kicking method

•Shaft method

•Pipe jacking method

•Box jacking method

8. Cut and Cover Method of Tunnel Construction
Cut and cover method of tunnel construction is generally used to build shallow tunnels.
In this method, a trench is cut in the soil and it is covered by some support which can be capable
of bearing load on it.
The cutting can be done by two methods:
A.One is bottom up method in which a tunnel is excavated under the surface using ground
support.

B.Another method is top-down method in which side support walls are constructed first by
slurry walling method or contiguous bored piling. Then roof is located on the top of the
walls and excavation is carried out. Finally, base slab is constructed. Most of the
Underground metro rail stations are constructed using cut and cover method.

9. Underground
Structures

10. Bored Tunnel
Method
•Bored tunnel method is modern technology.

•Tunnel boring machines are automatically and makes the entire tunneling process
easier. It is also quicker process and good method to build tunnel in high traffic
areas.

•Tunnels boring machines (TBM’s) are available in different types suitable for
different ground conditions. These machines can be used in difficult conditions
such as below the water table etc.

•A special pressurized compartment is provided for TBM to work in below water
table conditions. The workers should not enter that compartment except for
repair works. Care should be taken while TBM is in working conditions. The only
difficulty with this TBM is its heavy weight. So, transportation is difficult and
costlier.

11. TUNNEL BORING MACHINE

12. •The immersed tunnel, also called Sunken Tube, is a tunnel construction method
commonly used for crossing a body of shallow water.

•Sunk into a body of water and laid on or buried just under its bed They mainly serve
as road or rail tunnels, but immersed tunnels are also used for water supply and
electric cables.
Immersed tube tunnel

13. Tunnels normally are not straight
why?
•Mainly due to vision.
•The ambient light level is low in a tunnel.
•A straight tunnel would be dazzled by the brightness of the light at the end of
the tunnel.
•Hence curves are built so that the light level gradually increases.

14. ADVANTAGES OF THE TUNNELS

•Less susceptible to physical intrusion and natural disaster.

•Offer constant temperatures.

•Aren't susceptible to the fickle nature of aboveground weather, consume
less energy.

UNDERGROUND HOMES

•Generally costs 20-30%
more than the cost of
constructing conventional
houses.

•Caves and dugouts are the most
common structure.

•Are also resistant to fires
because of their concrete-and-
steel, construction and dirt
covering.

15. Shaft Method of Tunnel Construction

•In this method tunnel is constructed at greater depth from the ground surface.

•The shaft is built up to the depth where tunnel is required.

•Shaft is a permanent structure which is like well with concrete walls.

•At required depth, tunnels are excavated using TBM’s.

•Shafts are provided at both inlet and outlet of tunnels. Intermediate shafts are also
provided if tunnel is too long. After the construction process, these shafts can also
be used for ventilation purpose as well as emergency exits.

16. Clay kicking method

•In this method, a hole is excavated into the ground and after some depth tunnel is
excavated which is done by the clay kicker which lies 0n a plank at 45deg. angle.

•An excavating tool is provided under clay kicker foot. The excavated clay is
collected
by other worker.

17. •Pipe jacking method is used to construct
tunnels under existing structures like
road ways, railways etc.

•In this method, specially made pipes are
driven into underground using hydraulic
jacks. Maximum size of 3.2-meter
diameter is allowed for tunnels.
Pipe jacking method

18. Box jacking method
•Box jacking method is similar to pipe
jacking, but in this case instead of
pipes, specially made boxes are driven
into the soil.

•A cutting head is provided at the front
side of the box. Excavated matter is
collected within the box. Larger size
tunnels can be excavated using box
jacks up to 20 meters.