IJSRD - International Journal for Scientific Research & Development| Vol. 5, Issue 12, 2018 | ISSN (online): 2321-0613
Microtunneling
Ajinkya P. Khamkar2 Pratik S. Kapadnis3 Neel N. Ramjiyani4
Prof. N.G. Gore5
1,2,3,4,5
MGM College of Engineering and Technology, Kamothe, Navi Mumbai, India
Tanmay A.
Thakur1
Abstract— This project report on MICROTUNNELING is
intended to provide information regarding the use of
Microtunneling in today’s world. Significant technical
advances and increases in the utilization of Microtunneling
have occurred in the World in the past few years permitting
the installation underground of pipes in all ground
conditions with the minimum of surface disturbance.
Microtunneling techniques are providing wide range of
diameter and applications. Many problems of large diameter
tunnels and technically demanding tunnels are incorporated
due to Microtunneling. This project is specifically tailored
for those interested in Microtunneling and describes the
technique in depth together with comparisons with other
trenchless techniques. The project provides an in-depth
review of Microtunneling including all its aspects.
Key words: Pipe Jacking, Equipments of Microtunneling,
Curved Microtunneling
I. INTRODUCTION
Microtunneling is a process that uses a remotely controlled
Micro Tunnel Boring Machine (MTBM). In order to directly
install product pipelines underground in a single pass
Microtunneling is usually combined with the Pipe Jacking
method.
It is a trenchless method of pipe installation where
a pipe is jacked behind a Micro tunnel Boring Machine
which is shoved forward as the pipe is installed by avoiding
man entry. Generally guided by a laser and most often used
for the installation of gravity flow systems. For example
sewer and storm water or for other services where high
accuracy is required.
The need of providing long stretches of open trench
for pipe laying can be avoided by Microtunneling as they
cause extreme disturbance to the community.
In the U.S., Microtunneling has been used to
install pipe from 0.3 m to 3.7 m in diameter.
Microtunneling is currently the most accurate
pipeline installation method. Line and grade tolerances of
2.5 cm are the Microtunneling industry standard. This can
be significantly useful where a large maze of pipelines exists
underground.
II. HISTORY OF MICROTUNNELING
The origins of Microtunneling go way back into the early
1970’s where it was developed by the Japanese in order to
replace open sewers with underground gravity sewers in
urban areas. South Florida in 1984 was the first location in
the United States where Microtunneling work was initiated.
This tunnel project spanned over 182 meters while having a
pipe diameter of 1.82 meters. Originally Microtunneling
projects were only designed for construction of gravity
sewers, but with passing time they are now also used for
underground crossings of highways, railroads, runways, etc.
III. PIPE JACKING
Pipe jacking is supplementary method used along with
micro tunneling so as to push the sections of the concrete
pipes into tunnel drilled by micro tunneling boring machine.
A. Procedure of Pipe Jacking
1) Excavate and prepare the driving shaft.
2) Set up the jacking frame and the hydraulic jacks to
adjust to the proposed design line and grade by
providing a simple track to guide the pipe sections.
3) Install laser guidance system in the driving shaft which
is fixed in the back of the hydraulic jack pad to guide
the operator to jack the pipe in proper alignment and
slope
4) Lower the boring machine into the driving shaft and set
it by using an Auger machine.
5) Mate the jacking push plate to the shield or the tunnel
boring machine.
6) Advance the shield or the TBM through the prepared
opening in the forward shaft support structure. The
movement of the jacking machine is controlled by the
control panel outside of boring machine, whereas the
drilling operation is controlled by the control levers
inside the boring machine.
7) Retract the jacks and push plate to provide a space for
the pipe segment.
8) Place the first pipe segment on the jacking tracks.
9) Mate the push plate to the pipe and pipe to the shield or
the TBM.
10) Initiate forward advancement, excavation, and spoil
removal.
11) Repeat pipe jacking cycles until the complete line is
installed. The next section of pipe is lowered into the pit
and the above steps repeated.
12) Remove the shield or the TBM from reception shaft.
13) Remove the jacking equipment, IJS and the tracks from
drive shaft.
14) Restore the site as required.
B. Scope of Pipe Jacking
Pipe jacking is used to install conduits below ground for a
variety of applications including:
 Sewerage pipelines
 Storm water pipelines
 Road and rail culverts
C. Benefits of Pipe Jacking





Inherent strength of lining.
Smooth internal finish giving good flow characteristics.
No requirement for secondary lining.
Considerably less joints than a segmental tunnel.
Prevention of ground water ingress by use of pipes with
sealed flexible joints.
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
Invert channels can be provided in larger pipes to
contain the dry weather flow of a sewer in a combined
system.
IV. CONSTRUCTION PROCEDURE
Microtunnelling, being a modern method of laying of pipes,
has fine and systematic construction procedure leading to
great accuracy and clean, tidy site. The method can be
explained through the points stated below:
1) Excavation for commencement shaft and Transportation
of different units and plants to the site.
2) Construction of thrust wall in the direction of progress
of work and Installation of hydraulic jacking frame
facing it.
3) Setting of slurry separation tank, Bentonite and slurry
pumps, slurry lines, controlling container and
Positioning of cranes, Backhoes, Pipes etc.
4) Fixing Laser guidance system, followed by Lowering of
Micro Tunneling Boring Machine (MTBM) with
suitable cutting head on the launch skid.
5) Connecting all of the slurry lines and cables with
appropriate connections of MTBM.
6) Setting and matching the coordinates of MTBM with
those in controlling cabin with the help of Laser
guidance system as per desired alignment of work.
Starting up of the MTBM.
7) Lowering of first pipe section on launching skid and
jacking it into the drilled tunnel following MTBM.
8) Disconnecting the cables and slurry lines indicating
cessation of first section of pipe. Lowering of
succeeding section of pipe.
V. EQUIPMENTS
Capital equipments used in microtunnelling process are:
A. Micro Tunneling Boring Machine
MTBM is a powerful tunnel boring machine used for
drilling underground tunnel of desired diameter, with
hydraulic, pneumatic or auger spoil removal system. As per
different conditions of underground soil strata, different
cutter heads are chosen. (i.e. specially designed for clay, silt,
sand, rock). Machine consists of two parts namely shield
and can. It houses cutter head, conical crusher, hydraulic
motors and receiver of the laser. The machine operates on
the diesel generator. Its cost varies from Rs 1 crore to 20
crore.
B. Excavator and Crane
For excavation of the commencement shaft, intermediate
shaft and receiving shaft the excavator is used. Depending
upon the depth of excavation and groundwater table,
suitable type of excavator is used. The crane, preferably of
compact size and capable of lifting and lowering the
concrete pipe sections and MTBM is used. The crane is
desired to be able to carry the controlling container and
slurry separation tank in case of emergency.
C. Controlling container
It is the most important unit of process. Different controlling
computers, GPS, controls of Laser, slurry and bentonite
cables controller, pressure sensor are housed into it. The
progress of MTBM is measured by observing the X and Y
coordinates obtained through Laser guidance system. By
adjusting them, the machine can be given desired upward or
downward deviation in path.
D. Diesel Generator and Slurry Separation Tank
Diesel generator supplies power to whole microtunnelling
process. The slurry separation tank consists of two units. In
first one the slurry is screened and in later one it is kept still
so that the debris is settled and water is reused. The settled
debris is either dumped or used for leveling low lying areas.
E. Other Miscellaneous Units
The shafts of higher depth are Shortcreted from inside for
preventing collapse. A meter gauge is installed at thrust wall
for measuring the progress of work. Loaders and trucks are
used for hauling the excavated soil and screenings.
Bentonite is injected throughout the process for lubricating
the machine.
VI. CURVED MICOTUNNELING
For curved micro tunneling Laser Total System or a Gyro
Navigation System is used for guidance while introducing
the pipe in a curve. This system is created for the guiding
long distance and curved pipe jacking applications for pipe
diameters of more than 1m.
A servo motorized Laser Total Station which is
mounted inside the tunnel on a special bracket is the main
component of the system and it moves along together with
the pipeline.
The known as-built position of the already installed
pipes helps in continuously determining the actual position
of the laser total station
The company named Huxted Tunneling LLC
recently completed a 480 foot long, 84” Reinforced
Concrete Pipe micro tunnel drive with a 700 foot radius
horizontal curve which was accomplished using 10 foot long
pipe segments.
VII. MAINTENANCE
Various cleaning methods include:
A. Flushing
Flushing is efficient & effectual process of cleaning main.
Corrosive materials are easily flushed away during the
process throughout the main. Sediment, gelatinous material
and stagnant water are also flushed during flushing.
Flushing is most effective with flow of six feet per second.
B. Drag Cleaning
This cleaning method is carried out by a pig liner both
discharge & receiver point. Cables attached devices are
pulled at D/S side for removing heavy encrustation from
inside pipe.
C. Hydraulic Jet Devices
This device is used to dislodge and remove obstruction by
using high pressure jets of water. This method generates
more amount of waste water which is to be disposed off in a
suitable manner.
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(IJSRD/Vol. 5/Issue 12/2018/033)
D. Chemical cleaning
Acids are used for cleaning mineral deposits within the
pipeline. It requires special handling & skilled labour. After
the completion of process, flushing should take to neutralize
the acidic reaction.
E. Air cleaning
This method is used for small diameter pipes in which high
air pressure is injected with small amount of water to
remove scale and deposits inside wall of pipe. Air velocity
and cleaning efficiency gets reduced due to valves, bends &
appurtenances.
VIII. APPLICATIONS AND BENEFITS
A. Applications
Microtunneling method is efficiently used by pipe jacking
and includes installation of new drainage construction,
telecommunication cable, oil pipelines, culverts etc. MTBM
is suitable for mixed face, soft soil & rock tunneling. It is
easily operate able below 3 bar pressure water table.
MTBM technique is for rehabilitation of existing
sewer structures. Replacing the old sewer pipeline with the
new one can be easily done by trenchless techniques.
REFERENCES
[1] Mohamed Marzouk, Moatassem Abdallah, and Moheeb
El-Said (2010) Modeling Microtunneling Projects using
Computer Simulation. Journal of Construction
Engineering and Management Vol. 136
[2] Palmer, P.E (2013) Specifying Microtunneling
Installation Tolerances. Journal of North America
Microtunneling Association.
[3] Bernie Krzys, Mike Kezdi(2015) Innovations in
Microtunnelling and Ground Improvement. Tunnel
Business Magazine.
[4] www.quoradigest.com
[5] www.google.com
[6] www.wikipedia.com
[7] www.portlandoregon.gov/bes/article/486793
B.
1)
2)
3)
4)
Benefits
It creates very less pollution
IT can be used in difficult geological situations
This technique is environmentally sound technology
Speed of construction is also fast due to skilled labour
& easy machineries.
5) It can be also be used in congested areas likes roads,
highways, buildings, railway lines.
IX. CONCLUSION
The demand for utilities provision is directly proportional to
the population in urban areas. Our paper concludes that for
constructing any underground pipeline projects such as oil
pipeline, gas pipeline, water mains, sewer etc. in a densely
congested area the best and most efficient method is
Microtunneling. With respect to development in
construction industry today and a big sum of amount is
granted in the budget of India for the infrastructural
development
Thus the Microtunneling process shall be used in
future so that we can save space, money, time and make use
of most of the urban area available.
X. FUTURE SCOPE
Microtunneling is recently adopted construction technique.
Thus it has high potential of development in the future. In
future, there will be scarcity of open spaces in urban areas
and thus underground construction will be only possible
option for further fulfillment of demand of infrastructure
utilities for the population of urban areas.
Thus the project report gives the basis for future
development of the Microtunneling construction process.
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