Transcript Tunnelling Methods - Civil Engineering Society

TUNNELING METHODS
CONTENTS
INTRODUCTION
 REQUIREMENTS OF TUNNEL
 MAIN PURPOSES
 PROCEDURES INVOLVED
 METHODS OF TUNELLING
 METHOD TO SELECTION
 THE OTHER SIDE

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,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)
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.
MAIN PURPOSES
1.IN ROAD TRAFFICS
2.IN SEWERS
3.IN MININGS
4.IN RAIL TRAFFICS
5.IN HYDROELECTRIC
STATIONS etc.
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

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
way.
is performed by experts in a scientific
 Many
governments grants permission for
tunneling after finding a go certificate in
excavation.
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
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 .
tunnel construction methods:

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




Classical methods
Cut-and-cover
Drill and blast
Tunnel boring machines (TBMs)
Immersed tunnels
Tunnel jacking
Other methods .
Classical
Methods

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


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 was done by hand or
simple drilling equipment.
Supports were predominantly
timber, and transportation of
muck was done on cars on narrow
gauge tracks and powered by
steam.
Progress was typically in multiple
stages i.e. progress in one drift,
then support, then drift in another
drift, and so on.
The lining would be of brickwork.
These craft-based methods are no
longer applicable, although some
of their principles have been used
in combination up to present day.
Nevertheless some of the world’s
great tunnels were built with
these methods.
The English method (crown-bar
method, figure left) 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

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.

The German method (core-leaving method) provided a series of box

The Belgian system (underpinning or flying arch method) started

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.
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.
ROAD HEADERS
CUT AND COVER METHOD
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 cohesionless
soils.
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.
HOW DRILL AND BLAST IS BEING DONE.
MECHANICAL DRILLING AND CUTTING-CRUSHING
STRENGTH OF ROCK
TBM
 In
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.
IMMERSED TUNNELS
1.THIS TYPE OF TUNNELS ARE
PARTLY OR WHOLLY ARE
UNDERWATWER.
2.THEY DO NOT BLOCK THE
ROOT FOR SHIPS SO THERE IS
NO PROBLEM OF
CONGESSION OF TRAFFIC AS
IN CASE OF BRIDGES OVER
RIVERS OR SEAS.
TUNNEL JACKING
1.IT IS A PROCESS TO MAKE
TUNNELS IN ALREADY
EXISTING BOADIES SUCH AS
ROADS ,RAILWAYS.
2.IN THIS METHOD ESPECIALLY
MADE PIPES ARE PUSHED BY A
HYDRAULIC RAM IN GROUND .
3.MAXIMUM DIAMETER OF
TUNNEL BY THIS METHOD IS
AROUND 2.4 METER.
The choice of tunnelling method
may be dictated by:
geological and hydrological conditions,
 cross-section and length of continuous tunnel,
 local experience and time/cost considerations (what is
the value of time in the project),
 limits of surface disturbance, and many others factors.
 Tunnel methods .
 Required speed of construction.
 Shape of tunnel.
 Managing the risk of variations in ground quality

THE OTHER SIDE
 Beside
of many security measures ,
tunnelling is still not full 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.
.
THE END

.