A tunnel boring machine (TBM) excavates tunnels with a circular cross section through a variety of soil and rock strata. TBMs can bore through varying ground conditions including soft ground, mixed face conditions and hard rock. The document discusses different tunnel construction methods such as drill-and-blast, TBMs, cut-and-cover and immersed tunnels. It also describes the various processes involved in tunnel boring including drilling, excavation, muck removal, ground treatment and tunnel lining. Selection of the appropriate construction method depends on geological conditions, tunnel dimensions, construction timelines and other factors.

1. TUNNEL BORING MACHINES

2. CONTENTS
 INTRODUCTION
 REQUIREMENTS OF TUNNEL
 MAIN PURPOSES
 PROCEDURES INVOLVED
 METHODS OF TUNELLING
 INSTRUMENTATION USED
 METHOD TO SELECTION
 THE OTHER SIDE

3. A tunnel is an underground passageway,
completely enclosed except for openings for
egress, commonly at each end.
A tunnel may be for road traffic,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)
 it is very useful where bridge fail to fulfill
requirements like in sea ,in urban area
and in mountains.
 efficient when compared 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.
INTRODUCTION
WHAT IS A TUNNEL?

4. MAIN PURPOSES
IN ROAD TRAFFICS
IN SEWERS
IN MINING
IN RAIL TRAFFICS
IN HYDROELECTRIC STATIONS ETC.

5. THE PROCESS FOR BORED TUNNELLING
INVOLVES ALL OR SOME OF THE FOLLOWING
OPERATIONS:
 Probe drilling (when needed)
 Grouting (when needed)
 Excavation (or blasting)
 Supporting
 Transportation of muck
 Lining or coating/sealing
 Draining
 Ventilation

6. PROBE DRILLING
 This type of drilling is done in order
to find out suitable method for drilling
 It consist of drilling in sample, by
various method to find most suitable
 It is necessary part of all drilling
operation .
GROUTING
 It is the process of providing
additional support to drilled mine.
 It is done by a liquid called grout
,consist of water ,cement ,color
tint and sometime fine gravel .
 Good surface is achieved .
EXCAVATION
 Excavation is the digging and recording of
artifacts at an archaeological site.
 It is necessary to know the archaeological
importance of a site before digging .
 This is performed by experts in a scientific
way.
 Many governments grants permission for
SUPPORTING
 After initial mining , tunnel need supports
for further processing .
 For the sake of life a perfect planning is
needed for support.
 In ancient time timber and masonry were
the main methods.
 Today support is provided by injecting final
pipe or building it completely before further
tunneling

7. TRANSPORTATION OF MUCK
 In ancient time transportation was done
by steam engine and by Manual
transport.
 Today it is done by modern methods
and process is automatic .
 TBMs are also come with proper
arrangment for the transport of muck.
LINING OR COATING
 Lining of proper material is done by
modern methods like polishing ,painting
to prevent wear and tear and corrosion.
 Very necessary part where corrosive
metals are being used.
DRAINING
 Draining is the process to remove the
water or other liquid from working site
 Very important where water level is
very high.
 Pumps and pipes are used for this
purpose.
VENTILATION
 Proper ventilation is required for
safety of workers.
 This is done by proper checking of
oxygen and other parameters .
 Proper installations for exit of
hazardous gasses coming out from
tunneling .

8. TUNNEL CONSTRUCTION METHODS:
 Classical methods
 Cut-and-cover
 Drill and blast
 Tunnel boring machines (TBMs)
 Immersed tunnels
 Tunnel jacking
 Other methods .

9. CLASSICAL METHODS
 Among the classical methods are the Belgian,
English, German, Austrian, Italian and
American systems. These methods had much
in common with early mining methods and
were used until last half of the 19th century.
 Excavation done by hand or simple drilling
equipment.
 Supports were predominantly timber, and
transportation of muck was done on cars on
narrow gauge tracks
 Progress was typically in multiple stages
 The lining would be of brickwork.
These craft-based methods are no longer
applicable.

10. THE ENGLISH METHOD
 Crown-bar method- started from a central
top heading which allowed two timber crown
bars to be hoisted into place, the rear ends
supported on a completed length of lining,
the forward ends propped within the central
heading. Development of the heading then
allowed additional bars to be erected around
the perimeter of the face with boards
between each pair to exclude the ground.
The system is economical in timber, permits
construction of the arch of the tunnel in full-
face excavation, and is tolerant of a wide
variety of ground conditions, but depends on
relatively low ground pressures.

11. THE AUSTRIAN (CROSS-BAR)
METHOD
required a strongly constructed central bottom
heading upon which a crown heading was
constructed. The timbering for full-face
excavation was then heavily braced against the
central headings, with longitudinal poling boards
built on timber bars carried on each frame of
timbering. As the lining advanced, so was the
timbering propped against each length to
maintain stability. The method was capable of
withstanding high ground pressures but had high
demand for timber.

12. THE GERMAN METHOD
(core-leaving method) provided a series of box headings within which the successive sections of
the side walls of the tunnel were built from the footing upwards, thus a forerunner of the system of
multiple drifts. The method depends on the central dumpling being able to resists without excessive
movement pressure transmitted from the side walls, in providing support to the top 'key' heading
prior to completion of the arch and to ensuring stability while the invert arch is extended in sections.
THE BELGIAN SYSTEM
(underpinning or flying arch method) started from the construction of a top heading, propped
approximately to the level of the springing of the arch for a horseshoe tunnel. This heading was
then extended to each side to permit construction of the upper part of the arch, which was
extended by under- pinning, working from side headings. The system was only practicable where
rock loads were not heavy.
The first sizeable tunnel in soft ground was the Tronquoy tunnel on the St Quentin canal in France
in 1803, where the method of construction, based on the use of successive headings to construct
sections of the arch starting from the footing, was a forerunner to the German system described
above.

13. Road headers

14. CUT & COVER METHOD
 The principal problem to be solved in connection
with this construction method is to how to maintain
surface traffic, with the least disturbance during the
construction period. One method is to restrict traffic
to a reduced street width, another to direct traffic to
a bypassing street.
 Another way of supporting the sidewalls of open
trenches is to substitute sheet-pile walls by concrete
curtain walls cast under bentonite slurry (ICOS
method), and using steel struts. This is especially a
requisite in narrower streets trimmed with old
sensitive buildings with their foundation plane well
above the bottom level of the pit. This type of trench
wall becomes a requirement for maintenance of
surface traffic due to the anticipation of vibration
effects potentially harmful to the stability of buildings
with foundations lying on cohesion less soils.

15. 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.

16. HOW DRILL AND BLAST IS BEING DONE.

17. Mechanical Drilling and Cutting-Crushing Strength of rock

18. TBM
 Various size Tunnel Boring Machines(TBM) are used for
drilling a vast type of tunnels .
 Transportation of muck , supporting and all other actions are
done automatically.
 Very useful in boring tunnel where all other methods fail.
 A main method in use in now a days.

19. FULL FACE SLURRY TBM in South Africa

20. IMMERSED TUNNELS
• THESE AREA PARTLY OR WHOLLY
ARE UNDERWATWER
• THEY DO NOT BLOCK THE ROUTE
FOR SHIPS
• HENCE NO PROBLEM OF
CONGESSION OF TRAFFIC AS IN
CASE OF BRIDGES OVER
RIVERS OR SEAS

21. TUNNEL JACKING
• IT IS A PROCESS TO MAKE TUNNELS
IN ALREADY EXISTING BODIES SUCH
AS ROADS ,RAILWAYS
• IN THIS METHOD ESPECIALLY MADE
PIPES ARE PUSHED BY A HYDRAULIC
RAM IN GROUND
• MAXIMUM DIAMETER OF TUNNEL
BY THIS METHOD IS AROUND 2.4
METER

22. The choice of tunneling method may
be dictated by :-
 Geological And Hydrological Conditions
 Cross-section And Length Of Continuous Tunnel
 Local Experience And Time/Cost Considerations
 Limits Of Surface Disturbance
 Tunnel Methods
 Required Speed Of Construction
 Shape Of Tunnel
 Managing The Risk Of Variations In Ground Quality

23. THE OTHER SIDE
 Beside of many security measures , tunnelling is still not fool
proof.
 Failure of automatic system will cause deadly results as
depicted in Hollywood flick Die Hard 4.0.
 High cost than bridges, but more fruitful from previous.

24. Drill-and-Blast Method
1. A number of holes are drilled
into the rock
2. They are then filled with
explosives
3. Detonating the explosive
causes the rock to collapse
4. Rubble is removed and the
new tunnel surface is
reinforced
5. Repeating these steps will
eventually create a tunnel

25.  The positions and depths of the
holes and the amount of
explosive in each hole are
determined by a carefully
constructed pattern
 Together with the correct
timing of the individual
explosions, will guarantee that
the tunnel will have an
approximately circular cross-
section

26. • The machine, known as
Jumbo tunneling machine
• Used to drill and form holes
inside the tunnel for placing
of explosive
• Machine is computer
controlled and can drill 3
holes at the same time with
direction or angle precisely
set

27. Principle :-
Subdivide the tunnel section into
several arched smaller sections for the
sake of easier control and safer
supporting during excavation
The newly formed surfaces are often
required to temporary supported by
girder sections, shotcrete, nails or
anchors.
Tunnel Construction using New Austrian
Tunnel Method

29. A trial tunnel section
being formed
Tunnel Construction using Drill-and-
Blast Method

30. • After the tunnel formed by
drill and blast process, the
newly formed tunnel surface
is to be lined with an in-situ
concrete lining to stabilize
the exposed soil or rock
faces
• The photo shows the gantry-
type formwork used to form
the in-situ concrete lining.
Tunnel Construction using Drill-and-
Blast Method

31. A trial section of tunnel
excavation making use
of the concept of New
Austrian Tunnel
Method
Tunnel Construction using New Austrian
Tunnel Method

32. Tunnel Construction using Tunnel Boring Machine
(TBM)
The tunnel boring machine for the
forming of the 3.8m diameter tunnel
tube on Butterfly Valley side.

33. Tunnel Construction using Tunnel Boring Machine
(TBM)
• Close up of the cutter head.
• The cutting disc can cut into hard
rock and the granulated spoils will
be collected and removed by a
conveyor system that is positioned
immediate at the back of the
cutting head.

34. Tunnel Construction using Tunnel Boring Machine
(TBM)
Soil disposal wagons at the disposal
area on Butterfly Valley side portal.
The spoil will be kept at this location
waiting for the removal off-site by
dumping vehicles.

35. Tunnel Construction using Tunnel Boring Machine
(TBM)
Arrangement of the portal as viewed
from the tunnel exit. The spoil disposal
area is located on the right side of the
exit with rail track heading to that
direction. Rail track on the left is the
depot and servicing centre for the soil
disposal wagons, as well as for general
loading and unloading purposes.

36. Tunnel Construction using Tunnel Boring Machine
(TBM)
A view of the tunnel interior with the
partly formed lining, tunnel supporting
girders, rail track for soil disposing
wagon, ventilation hose and other
supply pipe lines etc.

37. Tunnel Construction using Tunnel Boring Machine
(TBM)
• A similar tunnel boring machine employed for the
forming of a cable tunnel for the Hong Kong
Electric on the Hong Kong Island side.
• Observe the hydraulic jack systems behind the
cutter head that enable the machine to stabilize
itself, pushing forward, or even slight adjustment
of its heading direction.

38. Tunnel Construction using Tunnel Boring Machine
(TBM)

39. Tunnel Construction using Tunnel Boring Machine
(TBM)
The working principle of the mixed-ground earth
pressure balanced tunneling machine under the
open mode and earth pressure balanced mode.

40. Tunnel Construction using Tunnel Boring Machine
(TBM)

41. Tunnel Construction using Tunnel Boring Machine
(TBM)

42. Tunnel Construction using Tunnel Boring Machine
(TBM)
The cutter head is
being connected to
the shield of the
EPBM by the help
of a track-mounted
gantry crane
positioned on the
ground level. The
rows of steel tubes
on the background
are lateral support
used to stabilize the
25m deep tunnel
shaft.

43. Tunnel Construction using Cut-and-Cover Method
Large amount of cut-and-cover
tunnels were constructed in the
MTR Tseung Kwan O Line in the
reclaimed land of TKO New Town

44. Tunnel Construction using Cut-and-Cover Method
Cut-and-cover tunnel constructed in difficult environment

45. Tunnel Construction using Cut-and-Cover Method
Box-section tunnel tube constructed inside the tunnel
trench using a set of traveling-type tunnel formwork

46. Tunnel Construction using Immersed Tubes
Western Harbour Crossing is
constructed using precast oncrete
immersed tube sections. A total of
12 sections have been used, each
measures 113m x 33.5m x 8.5m
high and weighs about 35,000 tons.
The photo shows one of the 3
batches of immersed tubes being
formed in the casting yard at Shek
O, HK

47. Tunnel Construction using Cut-and-Cover Method
The arrangement of the approach tunnels on West
Kowloon Reclamation side. As can be seen here, the
ventilation building also serves as the coupling structure to
receive the first approaching immersed tube. After the
tube being connected, the water embraced by the
elbowing land would be filled to
secure the coupling connection and make the tube land-
bound.

48. Tunnel Construction using Cut-and-Cover Method
The second immersed tube being towed to the launching
position for sinking and connecting onto the first tube. The
first tube at this stage has already been firmly positioned
at the seabed and cannot be seen on the surface.

49. Tunnel Construction using Cut-and-Cover Method
Touching up of the land
surface after the completion
of the immersed tube
connection. Note also the
construction of the tunnels
for the Airport Railway on
the right hand side of the
reclaimed land.

50. HAMMER TUNNELING HEAD MACHINES
 Operating weight – 18-45 tons
 Hammer/bucket combinations
 Hydraulic cutters and rock breakers
 Mucking tools
 Powerful diesel engines and electric
motor: with diesel drive into the tunnel
and at the tunnel face using emission
free electric motor
 Conveyor belt to rapidly move back the
excavated material

51. MUCKING & LOADING
MACHINES
 Extremely versatile applicable to varied
geological formations
 Digging and loading machines in soft
rock
 As loading machines with typical drill
and blasting heads
 Scaling the tunnel face
 Inverting
 Powerful loading performance

52. TUNNEL EXACAVATOR
•Efficient and precise
•Upper carriage with short tail permits large swing radius
•Along with swing bucket dipperstick exhibitshigh break
out forces
•Turbo diesel engines
•165kW diesel engines with high pump capacity allows
use of powerful drill rigs

53. BALLAST LOADING
MACHINES
 Excavation loading and conveyance
takes place in the same track
 Slewing of conventional crawler not
required
 Loading capacity – 3-4 cu.m. per min

54. ELECTRIC & SPECIAL
EXCAVATORS
 Salt mining
 Removal of cement residues in
furnace
 Demolition

55. HYDRAULIC CUTTING
UNITS
 Adjustable to resp
operating conditions
 Varies from 15kW to
120kW
 Low noise cutting
operation, low vibration,
smooth and gentle use
 CUTTING DRUMS- for
tree stump cutting
anddust removal
systems

56. SPECIAL MACHINES
 Crawler unit based road
heading machine
 Universally rotating and
swiveling
 Cutting boom cuts profiles
accurately
 For underground transport-
quick disassembly &
reassembly

57. TECHNICAL
SPECIFICATIONS