Description about micro-tunneling method for underground construction of sewage tunnel

1. 1
Laying of RCC Drainage Gravity Line by
Microtunneling Method
Industrial Training Report
Submitted to
Partial fulfilment of the requirements
for the degree of
BACHELOR OF TECHNOLOGY
in
Civil Engineering
by
Patel Poojan HiteshBhai
ID No: 14cl076
Under the supervision of
Asst. Prof. Ms. Neha Chauhan
March 2018
MANUBHAI SHIVABHAI PATEL DEPARTMENT OF CIVIL ENGINEERING
FACULTY OF TECHNOLOGY AND ENGINEERING
CHAROTAR UNIVERSITY OF SCIENCE & TECHNOLOGY
CHANGA – 388421, GUJARAT, INDIA

2. 2
CERTIFICATE
This is to certify that I have been supervising the Industrial Training (CL410.01) of Patel Poojan
Hiteshbhai (14CL076) for the partial fulfillment of Degree of Bachelor of Technology in Civil
Engineering.
This Project report is comprehensive, complete and fit for evaluation. The results of the report in
part or whole have not been submitted to any other Institute / University for the award of any
degree or diploma.
Assistant Professor
Ms. Neha Chauhan
Faculty Supervisor
Date:

3. 3
ACKNOWLEDGEMENT
I would like to thank, Manubhai S Patel Department of Civil Engineering, Chandubhai S
Patel Institute of Technology, Charusat University, Changa. for designing a course keeping
in mind the importance of practical knowledge in career as an acting engineering, which has
enabled me to undergo such training.
I would like to extend my hearty gratitude to my Faculty Guide Asst. Prof. Ms. Neha Chauhan
who had always been very cooperative and had helped me a lot in the process of finalizing my
detailed compressive report.
I have undergone eight weeks of training at ITD CEMENTAION INDIA LTD. I had lots of
experience there and so I would like to thank Mr. Adhir Bose & Mr. Hemant Joshi for
granting me a permission to work on his site and helping with each and every detail.

4. 4
ABSTRACT
Civil engineering is a vast field; various types of work are being done under civil engineering.
Our college have industrial training programme in final year and project training is a very
important aspect of technical studies as it provided an opportunity to expose one’s to the
industrial ambience, even before we complete our graduation. It is an opportunity to use
theoretical knowledge in practical circumstances and enhance technical skills
This project presents comprehensive information about training of Providing and laying RCC
drainage gravity line by micro-tunnelling method by ITD CEMENTAION INDIA LTD and
various activities done within the training period from 5th February to 31st March 2018.
There were many things I experienced and learned during the eight weeks of training. The whole
training was very informative. This report includes theoretical background of site activities,
proper method for Construction work at site and includes various points which should be kept in
mind while doing construction work at site.

5. 5
CONTENTS
ACKNOWLEDGEMENT
ABSTRACT
CHAPTER 1: COMPANY DETAILS
1.1 Introduction ........................................................................................................................ 8
1.2 Mission & Aim ................................................................................................................... 8
1.3 Core Principles ................................................................................................................... 9
1.4 Areas of Operation .............................................................................................................. 9
1.5 Iconic Projects ................................................................................................................... 10
1.6 Share Details ...................................................................................................................... 11
1.7 Company Address .............................................................................................................. 11
Chapter 2: Project Detail & Information
2.1 General Information............................................................................................................ 12
2.2 Schematic Layout (As On 25th December 2017) ............................................................... 13
2.3 Scope of Work ................................................................................................................... 13
2.4 Information About Microtunneling.................................................................................... 14
2.5 Open-Cut Vs Microtunneling............................................................................................. 15
2.6 Typical Microtunneling Set Up ......................................................................................... 17
Chapter 3: Project Execution Work
3.1 Planning ............................................................................................................................. 18
3.2 RCC Pipes Casting ............................................................................................................ 18
3.2.1 Scope of Work ................................................................................................................ 18
3.2.2 List of Major Materials and Machineries ....................................................................... 19
3.2.3 Casting of RCC Jacking Pipes by Vertical Cast Method................................................ 19
3.2.4 Tests Performed ............................................................................................................. 22

6. 6
3.2.4.1 Three Edge Bearing Test............................................................................................. 22
3.2.4.2 Hydro Test .................................................................................................................. 23
3.2.4.3 Water Absorption Test................................................................................................. 23
3.3 Site Execution ................................................................................................................... 24
3.3.1 Shaft Construction ......................................................................................................... 24
3.3.1.1 Trail Pit........................................................................................................................ 24
3.3.1.2 Utilities Shifting........................................................................................................... 25
3.3.1.3 Cutting Edge Placing .................................................................................................. 25
3.3.1.4 Reinforcement and Shuttering .................................................................................... 26
3.3.1.5 Sinking of Shaft Wall ................................................................................................. 26
3.3.1.6 Bottom Plugging, Base Slab ....................................................................................... 27
3.3.1.7 Detail Drawing for Shaft Construction (Shaft No 21r) .............................................. 28
3.3.1.8 Bar Bending Schedule (Shaft No 21r) ....................................................................... 29
3.3.2 MTBM Launching, Jacking and Receiving .................................................................. 31
3.3.2.1 Facilitation Work ....................................................................................................... 31
3.3.2.2 Set Up and Lowering of MTBM................................................................................. 32
3.3.2.3 Important Points for Jacking....................................................................................... 34
3.3.2.4 Jacking Sequence ....................................................................................................... 34
3.3.2.5 Spoil Removal System ............................................................................................... 36
3.3.2.6 Removal of Equipment ............................................................................................... 36
3.3.2.7 Finishing Works ......................................................................................................... 37
Chapter 4: Conclusion
4.1 Conclusion ........................................................................................................................ 38

7. 7
LIST OF FIGURES:
No. Description Page no.
Figure 1 Iconic Projects of Company 10
Figure 2 Share History 11
Figure 3 Schematic Layout (As On 25th December 2017) 13
Figure 4 Open-Cut Vs Microtunneling 15
Figure 5 Typical Microtunneling Setup 17
Figure 6 Casting of RCC Jacking Pipes by Vertical Cast Method 21
Figure 7 Three Edge Bearing Test 22
Figure 8 Hydro Test 23
Figure 9 Trail Pit 24
Figure 10 Utilities Shifting 25
Figure 11 Cutting Edge Placing 25
Figure 12 Reinforcement and Shuttering 26
Figure 13 Sinking of Shaft Wall 27
Figure 14 Bottom Plugging, Base Slab 27
Figure 15 Detail Drawing for Shaft Construction (Shaft No 21R) 28
Figure 16 Bar Bending Schedule (Shaft No 21R) 29
Figure 17 Bar Bending Schedule (Shaft No 21R) 30
Figure 18 Setting Up Of MTBM 31
Figure 19 MTBM 32
Figure 20 Launching Of MTBM 33
Figure 21 Pipe Jacking 35
Figure 22 MTBM Receiving 36
Figure 23 Finishing Work 37
LIST OF TABLES:
No. Description Page no.
1 Detail of Pipe Diameter & Length 13

8. 8
CHAPTER 1: COMPANY DETAILS
1.1 Introduction
ITD Cementation India is a leading construction company in India operating for over eight
decades and has established its prowess across multiple lines of business: Maritime Structure,
Highways, Bridges & Flyovers, TBM & NATM Tunnels, Foundation & Specialist Engineering,
Airport, Industrial Structure & Building, Mass Rapid Transit Systems, Box Pushing, Tube
Heading & Micro-tunnelling, Hydroelectric Power, Dams & Irrigation, Water & Waste Water.
ITD Cementation India Limited (ITD Cem) has been a silent contributor to the infrastructure
growth in the country for over eight decades. ITD Cem has won the confidence & respect of their
clients, employees, stakeholders & all those whose lives are bettered in the process. Exploring
new and innovative methods of solving present day construction challenges is an integral part of
the Company’s philosophy. ITD Cem has pioneered the art of integrating engineering and
innovation with construction practices to maximize social benefits.
Over the years, ITD Cem diversified into core infrastructure segments developing expertise in
design and construction of large infrastructure projects. And with their skilled human resources,
expertise and state-of-the-art equipment at work, world-class projects are standing tall. ITD
Cem’s accreditation with ISO 9001:2008, ISO 14001:2004 and OHSAS 18001:2007
Certifications is a definitive assurance of the ITD Cem commitment.
1.2 Mission & Aim
Mission: To make ITD Cementation India Limited, country's leading construction company in
customer choice, quality and safety
Aim: ITD Cem aims to have a satisfied client-base, a strong and proactive workforce and to
deliver a quality product finished on time and to budget.

9. 9
1.3 Core Principles
 Customers come first.
 Employees are ITD Cem’s most important assets. Working conditions and training must
enable them to give their best.
 ITD Cem’s quality, health and safety standards are second to none.
 ITD Cem strives to ensure timely commencement and completion of projects.
 Good plants and machinery is ITD Cem’s wealth. They are always well maintained and in
good working order.
 Well-developed MIS systems and state-of-the art technology is ITD Cem’s priority.
 Environmental awareness and care for the world in which we live, is a part of ITD Cem’s
business philosophy.
 ITD Cem’s competitive edge is maintained through specialist skills and commitment to both
Training and R&D.
1.4 Areas of Operation
ITD Cem, together with the expertise of the parent Company, Italian-Thai Development Public
Company Limited Thailand, has successfully maintained its position as a market leader in the
field of Maritime Structures and Foundations. ITD Cem is a preferred contractor for Highways,
Bridges, Flyovers, Industrial Structures and has established a strong presence in Tunnels, Dams
and other Infrastructure projects. With its eight-decade reputation of constructing some of the
most prestigious & vital projects, ITD Cem has an array of Infrastructure projects to showcase.
They include large commercial and institutional buildings, elevated highways, viaducts,
railways, elevated and underground metro rail, airports, water and waste water treatment plants,
pumping stations, water conveying piping and utilities.

10. 10
1.5 Iconic Projects
Figure 1 Iconic Projects of Company

11. 11
1.6 Share Details
ITD Cementation is in the Construction & Contracting - Civil sector. The current market
capitalisation stands at Rs 2,849.96 crore. It is listed on the BSE with a BSE Code of 509496 and
the NSE with an NSE Code of ITDCEM.
Figure 2 Share History
1.7 Company Address
Registered & Corporate Office
ITD Cementation India Limited
National Plastic Building,
A Subhash Road,
Paranjape B Scheme,
Vile Parle (East),
Mumbai 400 057

12. 12
CHAPTER 2:
PROJECT DETAIL & INFORMATION
2.1 General Information
 Project Name: Implementation of 5.1 km water drainage scheme at Gorwa A.P.S. to
Shrenikpark Junction in Vadodara.
 Project Brief: The project involves providing and laying 1400/1800 mm dia R.C.C. jacking
pipe drainage gravity Line by micro tunnelling technology on B.P.C. Road from Gorwa
A.P.S. to Shrenikpark Junction in Vadodara.
 Sector: Water Sanitation
 Sub-Sector: Sewage collection, treatment and disposal system
 Project Status: Under Construction
 Nodal Authority: State
 Project Capacity: 5.1 KM (Kilometre)
 Project Authority: Vadodara Municipal Corporation
 Project Authority address: Khanderao Market Building, Rajmahal Road, Vadodara-390004,
Gujarat
 Project Contractor: ITD Cementation Limited
 Project Contractor address: Godrej Waterside & quot, Tower No. 1, Office 803, 8th floor,
Plot No. 5, Block-DP, Sector-V, Salt Lake City, Kolkata-700091, West Bengal
 Date of Award of Project: 08-May-2015
 Project Cost (as per Contract) in Rs Crore: 121.05

13. 13
2.2 Scope of Work
Table 1 Detail of Pipe Diameter & Length
No Pipe Dia. Unit
1 1500 mm Internal Diameter 1750 M
2 1600 mm Internal Diameter 1750 M
3 1825 mm Internal Diameter 1600 M
2.3 Schematic Layout (as on 25th December2017)
Figure 3 Schematic Layout (As On 25th December 2017)

14. 14
2.4 Information About Microtunneling
 Microtunneling is a trenchless construction method used to install pipelines beneath
highways, railroads, runways, harbours, rivers, and environmentally sensitive areas.
Microtunneling is defined as a remotely-controlled, guided, pipe-jacking operation that
provides continuous support to the excavation face by applying mechanical or fluid pressure
to balance groundwater and earth pressures. Support at the excavation face is a key feature of
microtunneling, distinguishing it from traditional open-shield pipe-jacking.
 Microtunneling requires jacking and reception shafts at the opposite ends of each drive. The
microtunneling process is a cyclic pipe jacking operation. A micro tunnel boring machine
(MTBM) is pushed into the earth by hydraulic jacks mounted and aligned in the jacking
shaft. The jacks are then retracted, and the slurry lines and control cables are disconnected. A
product pipe or casing is lowered into the shaft and inserted between the jacking frame and
the MTBM or previously jacked pipe. Slurry lines and power and control cable connections
are made, and the pipe and MTBM are advanced another drive stroke. This process is
repeated until the MTBM reaches the reception shaft. Upon drive completion, the MTBM
and trailing equipment are retrieved, and all equipment removed from the pipeline.
 Most microtunneling operations include a hydraulic jacking system to advance the MTBM
and pipe string, a closed loop slurry system to transport the excavated spoils, a slurry
cleaning system to remove the spoil from the slurry water, a lubrication system to lubricate
the exterior of the pipe string during installation, a guidance system to provide line and grade
control, an electrical supply and distribution system to power equipment, a crane to hoist pipe
sections into the jacking shaft, and various trucks and loaders to transport spoil off site.
 MTBMs have a rotating cutting head to excavate the ground material, a crushing cone to
crush larger particles into smaller sizes for transport through the slurry lines, a hydraulic or
electric motor to turn the cutting head, a pressurized slurry mixing chamber behind the cutter
head to maintain face stability, an articulated steering unit with steering jacks for steering
corrections, various control valves, pressure gauges, flow meters, and a data acquisition
system. Additionally, the MTBM has inline cameras to relay information to the operator and
a target system for guidance control. Precise control of line and grade is accomplished using
the guidance system and steering jacks to locate and steer the MTBM during a

15. 15
microtunneling drive. The guidance system usually consists of a reference laser mounted in
the jacking shaft, which transmits a beam onto a target mounted inside the articulated section
of the MTBM. This and other operational information is transmitted through wire cables to a
control cabin located on the surface.
 Microtunneling machines are capable of independently counter-balancing earth and
hydrostatic pressures. Earth pressure is counter-balanced by careful control of advance rates
and excavation rates of spoil materials. Groundwater pressure is counter-balanced by using
pressurized slurry in the soil-mixing chamber of the MTBM.
2.5 Open-cut vs Microtunneling
Figure 4 Open-Cut Vs Microtunneling

16. 16
 Because the microtunneling procedure involves a remotely-controlled steerable system to
install pipes and cables at the ground surface, it only requires a small tunnel boring machine.
As opposed to traditional open cut construction which can be destructive to the surrounding
site, microtunneling allows for a much more direct route.
 Microtunneling techniques offer advantages over traditional open cut construction and
therefore, have become the primary means of underground construction methods.
Microtunneling is said to be one of the most beneficial underground construction techniques
for everyone involved and the surrounding environment.
 The microtunneling method is very friendly on the environment because of its cleaner
process. Techniques used in the microtunneling and pipe jacking process ensure quantities of
both incoming and outgoing materials are reduced significantly. Not only is this less harsh on
the surrounding environment, but it boosts the safety benefits for the workers too.
 Combined with pipe jacking techniques, the microtunneling method is one of the most
environmentally friendly and safer underground construction process. Because open cut
trench construction normally has to follow existing pipe utilities, roadways and other
unobstructed surface, microtunneling offers a trendless construction that protects the
environment rather than destroys it.
 Microtunneling processes have proven to be an advantageous and practical method that not
only reduces environmental risks, but project costs too.
 The risk of injury to workers and the general public are reduced by using methods such as
microtunneling with more accurate systems still being achieved.

17. 17
2.6 Typical Microtunneling Setup
Figure 5 Typical Microtunneling Setup

18. 18
CHAPTER 3: PROJECT EXECUTION WORK
3.1 Planning
The first consideration is determining the pipeline line and grade. This may sound simple but
locating the position of your pipeline requires an intimate understanding of the ground
conditions, and the microtunneling equipment and its capabilities, in order to save costs and
avoid problems during construction. Following is some advice in planning your line and grade:
 Seek local knowledge of past construction projects. If you can obtain previous documents
from projects completed near the proposed site, you are that much ahead in getting started on
planning the line and grade of your project.
 Physically establish a line of sight between shaft locations. Sometimes you can identify
obstructions like a bridge support pier or sheet pile wall along the proposed tunnel route.
 Beware of existing utilities and service manhole inverts that “straddle” the tunnel route.
Therefor essential elements of planning are,
 Gather information about past projects in that area.
 Identify existing subsurface utilities and manholes.
 Establish a sightline between shafts.
 Data collection.
 Lab testing.
 Geotechnical investigation
3.2 RCC Pipes Casting
3.2.1 Scope of Work
 Casting of 1500 mm internal diameter RCC jacking pipes- 1750 M
 Casting of 1600 mm internal diameter RCC jacking pipes- 1750 M
 Casting of 1825 mm internal diameter RCC jacking pipes- 1600 M

19. 19
3.2.2 List of Major Materials & Machineries
Materials used:
 M50 grade ready mix concrete
 Reinforcement steel as per design drawing
 10 mm thick mild steel plates for collars
 Mould release agent
 Binding wires
 P.E lining- 2.5 mm thick, etc
Major machineries:
 Mobile crane
 Compressor
 Welding set
 Pumps
 Moulds & vibrators
 Gas cutting set
 Hydraulic jacks, etc
3.2.3 Casting of RCC Jacking Pipes by Vertical Cast Method
 Dimensional checks for each moulds w.r.t pipe design/ type of pipes
 Prepare and inspect reinforcing steel cage & ms collars
 Clean up mould and apply releasing agent
 Set up bottom mould and install inner mould
 Install P.E T ribbed lining in such way that the projected T portion faces concrete and plain
end is wrapped around inner formwork
 Fill the gap between the inner mould and bottom mould pallet whit jute twine and grease to
prevent leakage
 Install the reinforcement cage with cover block/PVC spacer and inspect for covering of
concrete

20. 20
 Set the header mould on the top of the pipe
 Install high frequency mould vibrators at designated location
 Concrete of approved grade is made and checked for slump cone test
 Concrete is poured directly from the transit mixer with the help of pouring chutes
 Periodic vibration by high capacity mould vibrators ensure proper compaction
 Finish the concrete surface with steel trowel
 De moulding outside formwork after 8 hours followed by inside formwork which is around
10 hours. This duration may vary based on climatic conditions, rainy season or night shift
when temperature is low
 Curing of fresh concrete jacking pipes by spraying water
 Lift wet cast pipe from the casting are after 12-14 hours then place it curing area
 Curing is continued by either wax-based curing compound/ water sprinkling
 Client, consultant &TPI name/ mark date of casting / identification no/ pipe type on RCC
jacking pipe is written.
 Carry out post concrete checks and transport to storage area.

21. 21
Figure 6 Casting of RCC Jacking Pipes by Vertical Cast Method

22. 22
3.2.4 Tests Performed
3.2.4.1 Three Edge Bearing Test
The external load crushing strength test with the load applied by three-edge bearing is the
accepted test method for both clay and concrete pipe. This same procedure may be employed in
the testing of concrete pipe if it is mutually agreed upon by the manufacturer and purchaser prior
to testing. Any mechanical or hand-powered device may be used in which the head that applies
the load moves at such a speed as to increase the load at a uniform rate of approximately 20
percent of the expected crushing load per linear metre per minute. The loading device shall be
calibrated within an accuracy of ±2 percent. The testing machine used for the load tests should
produce a uniform deflection throughout the full length of the pipe and shall be so substantial
and rigid throughout, that the distribution of the test load along the length of the barrel of the
pipe will not be appreciably affected by the deformation or yielding of any part of the machine
during the application of the load.
Figure 7 Three Edge Bearing Test

23. 23
3.2.4.2 Hydro Test
Hydrostatic testing is a type of pressure test that works by completely filling the component with
water, removing the air contained within the unit, and pressurizing the system up to 1.5 times the
design pressure limits the of the unit. The pressure is then held for a specific amount of time to
visually inspect the system for leaks. Visual inspection can be enhanced by applying either tracer
or fluorescent dyes to the liquid to determine where cracks and leaks are originating.
Figure 8 Hydro Test
3.2.4.3 Water Absorption Test
Cement will mix with more water than is required to eventually combine during hydration of
cement paste. As such, some voids will be left behind after the hydration process which affects
the strength and durability of concrete. With the presence of air voids in concrete, it is vulnerable
to penetration and attack by aggressive chemicals. Good quality concrete is characterized by
having minimal voids left by excess water and therefore, water absorption test for precast
concrete pipes is adopted for checking the quality of concrete in terms of density and
imperviousness.

24. 24
3.3 Site Execution
Major Execution work can be sequenced as below:
 Shaft construction by sinking method
 MTBM lowering and launching
 Pipe jacking
 MTBM receiving
3.3.1 Shaft Construction
Shafts should be capable of withstanding pre-determined jacking loads required to propel the
MTBM over the tunnel drive length and facilitate safe entry into the ground and exit out of the
ground.
3.3.1.1 Trial Pit
A trial pit is an excavation of ground in order to study or sample the composition and structure of
the subsurface, usually dug during a site investigation, a soil survey or a geological survey. Trial
pits are dug before the construction. They are dug to determine the geology and the water table
of that site. Trial pits are usually between 1 and 4 metres deep and are dug either by hand or
using a mechanical digger.
.
Figure 9 Trail Pit

25. 25
3.3.1.2 Utilities Shifting
Obstructive utilities like electrical line, gas line, telecommunication line, water line, sewer line,
etc are required to be shifted by informing appropriate authorities for further construction of
shaft.
Figure 10 Utilities Shifting
3.3.1.3 Cutting Edge Placing
Cutting edge is the lowermost part of rcc manhole and which cuts through the soil during
sinking.
Figure 11 Cutting Edge Placing

26. 26
3.3.1.4 Reinforcement and Shuttering
After placing down the cutting edge, reinforcement according to drawing is constructed which is
welded to the cutting edge as per specified drawing. Shuttering is also provided to support the
fresh concrete to attain its strength and structure.
Figure 12 Reinforcement and Shuttering
3.3.1.5 Sinking of Shaft
Sinking will be done by dredging the soil from the inside of shaft using clamshell grab operated
by crawler-mounted crane or manually. A proper method for maintain the alignment of shaft will
be monitored throughout the sinking process. In general shaft is allowed to sink under its own
weight. In case of any underground obstruction or hard strata is found which could not be
removed with usual sinking operation, water jetting method is used.

27. 27
Figure 13 Sinking of Shaft Wall
3.3.1.6 Bottom plugging, base slab
On reaching the founding level, the shaft will be plugged by plain cement concrete at bottom and
RCC bottom raft as per drawing. Concrete will be poured by tremie-method and concrete is
allowed to flow throughout. The bottom plug will generate bearing resistance for the shaft.
Afterward lowering of MTBM can be done.
Figure 14 Bottom Plugging, Base Slab

28. 28
3.3.1.7 Detailed Drawing for Shaft Construction (Shaft No 21R)
Figure 15 Detail Drawing for Shaft Construction (Shaft No 21R)

29. 29
3.3.1.8 Bar Bending Schedule (Shaft No 21R)
Figure 16 Bar Bending Schedule (Shaft No 21R)

30. 30
Figure 17 Bar Bending Schedule (Shaft No 21R)

31. 31
3.3.2 MTBM Launching, Jacking and Receiving
3.3.2.1 Facilitation Work
 Discharge pump is installed in sump pit at the bottom of shaft for dewatering
 Slurry tank and other ancillary controls nearby the jacking shaft are installed for initial
setting
 Temporary access ladder/ stair and platform are installed in suitable position
 Setting up jacking frame with guide rail at the bottom of jacking shaft to ensure that the pipes
will be advanced at right invert level, gradient and alignment
 Construction of mass concrete thrust wall for transmitting and dispersing the jack reaction
force to shaft wall and thereby to the soil behind. The face of the thrust wall must be
perpendicular to the bearing of the intended jacking alignment
 Launch seal is installed in concentric with the centre line of the pipe. The launch seal is made
of circular steel plates with rubber gasket strips bolted to the soft eye structure on shaft wall
where the pipe is to be jack through
 Setting up the main jack and accessories inside the jacking shaft is done
 Service unit like power supply, water supply and telecommunication etc are installed
Figure 18 Setting up of MTBM

32. 32
3.3.2.2 Set up and Lowering of MTBM
The equipment is set up at and around the shaft in the pre-determined arrangement for the drive.
The tunnelling machine is set up at ground level and connected up to the control container and
services. A series of test run are then carried out to determine that all equipment is functioning
correctly, and the drive parameter entered into the computer program. The services are then
disconnected, and the tunnelling machine is lowered into the shaft in preparation for jacking.
Mobile crane or gantry crane of suitable capacities are commissioned over the jacking shaft prior
to lowering of machine. A laser theodolite is placed to guide and monitor the alignment of the
jacking line.
Figure 19 MTBM

33. 33
Figure 20 Launching Of MTBM

34. 34
3.3.2.3 Important Points to be Consider for Jacking
 Before any particular pipe jack length commences sufficient number of standard, lubricating
pipes and intermediate jacking assemblies shall be ensured for continuous operation
 Suitably designed RCC pipes are to be used
 The jacking force applied by the thrust pit jacks or an intermediate jacking station shall not
exceed the design allowable distributed or deflected load for any pipe being jacked
 Pipe jacking, once commenced shall be performed as one continuous operation until
completion.
 A lubrication or ground support fluid, such as bentonite, shall be injected into annulus
between the exterior of the pipe and the ground. This fluid shall be maintained till end of
jacking for the span.
3.3.2.4 Jacking Sequence
 The shield is jacked until there is sufficient space for the first jacking pipe to be installed
 The shield machine and slurry pumps are then stopped, and all electrical cables and slurry
lines are disconnected in the jacking shaft
 The jacks are retracted, and all spacer removed in order to make space for the jacking pipe
 The jacking pipe is lowered into the shaft and placed on the guide rail
 After ensuring the pipe is joined properly to the tail of shield machine, the electrical cables
and slurry lines are reconnected
 Jacking of pipe is then resumed and the whole process is repeated until the shield machine
reaches about 300 mm from the face of the receiving shaft
 The exit ring and rubber seal are fixed if required depending on the ground water table
 Demolish concrete wall & reinforcement in front of the soft eye and jacking operation
resume until the whole shield machine is driven into receiving shaft
 The shield machine is removed, lifted up and transferred to next jacking shaft for
maintenance and to commence another line
 The jacking pipes are advanced to their final position and the alignment, gradient and levels
reconfirmed
 Upon completion of jacking the entire pipeline should be cleaned and repaired if required

35. 35
 The completed pipeline is then visually inspected
 During jacking, the alignment of the pipes is constantly checked by means of the laser
theodolite and laser target. Alignment corrections can be made using the steering jacks
situated in the shield machine
 Jacking force is monitored closely during jacking operations, bentonite slurry is pumped
through the grout holes in the jacking pipes to lubricate and reduce the frictional forces at
interface of the outside circumference of the pipe and the surrounding soil
 In long span where jacking operations cannot be completed in a day, the alignment and
gradient of the laser targeting system is checked time to time against the survey reference
points, prior to commencing pipe jacking. The survey reference points are also checked
against other survey control as and when required
Figure 21 Pipe Jacking

36. 36
3.3.2.5 Spoil Removal System
 The spoil removal system consists of counter flow unit, a charge pump, a pit by-pass unit, a
discharge pump, a flow meter, slurry tanks and slurry lines
 The bentonite-based slurry is mixed at the slurry tanks and pumped to the work face through
the cutter head of the slurry shield via the pit by-pass unit installed in the jacking shaft
 Spoil that has been excavated by the slurry shield machine is pumped through the discharge
line to the slurry tanks of the surface. The spoil is separated in the slurry tanks and the
remaining slurry is charged again to the slurry shield machine. The settled spoil in the tanks
is removed
 Since the slurry lines extend as the shield advances, it is essential to keep a certain level of
the flow rate to ensure the effective conveyance of the spoil. For this purpose, a flow meter is
fixed to the discharge line to detect and transmit the slurry flow rate to the operation board.
The slurry is also used to balance the ground water head, which is detected by the cutter face
pressure gauge in slurry shield machine. The slurry pressure applied to work face is
controlled by the pressure control valve of the pit by-pass unit in the jacking shaft
 The muck is pumped from the shield face to the sedimentation tanks at the top of the jacking
shaft. The solids are then removed from the sedimentation tanks and disposed off site
3.3.2.6 Removal of Equipment
When the head of the machine enters the receiving shaft, it is tools apart into two sections and
removed from the shaft using a mobile crane. The intermediate jacks are dismantled, and the
pipeline is pushed to its final position and tunnel eyes at each shaft are grouted with concrete or
sand cement grout and the entrance seal is removed.
Figure 22 MTBM Receiving

37. 37
3.3.2.7 Finishing Works
After completion of all inside manhole works RCC top slab as per approved drawing will be
casted along with extra heavy-duty manhole cover frame monolithically. The manhole frame will
project 25 mm above slab top. Necessary staging / shuttering will be done with support from the
steining walls. Staging and shuttering will be removed after 21 days i.e. after slab attains its full
strength. Bitumen carpeting will be applied on top slab expect on manhole cover area. It is
essential to avoid construction of manhole between shafts with in carriage way unless extremely
necessary.
Figure 23 Finishing Work

38. 38
CHAPTER 4: CONCLUSION
4.1 Conclusion
The training is a bridge between the theoretical knowledge and the practical or the reality work
at the field of construction or civil engineering work. I can conclude from my eight weeks of
training period that there was a great difference and bifurcations observed between the
theoretical aspects that I am taught about in the classes and the practical work aspects seen over
the construction site. As there is ample amount of scope for understanding much more when
practically experienced on the ongoing construction site. I achieved more knowledge in such
situation; while I had my endeavour over the practical work in that construction ambience around
me. I even observed that construction management was the most necessary subject on field
because there had been limited labours available and work was much more plus lots of restriction
and specifications were to be observed while working but if work in any case such as due to not
following the specifications written in the contract or the tender and etc. may be cause for
termination or deterioration in the working plan and schedule for the contractor resulting in
mismanagement over the site causing delay and even other great losses which were to be
experienced for both the firms that is the contractor and the client. Hence presence of mind and
human resource management with effective communication is necessary skills over the site.
Some of the benefits that I gain during training program are:
• Upgrading of theoretical knowledge and able to use it for practical work.
• Developing of communication skill.
• Developing skill of team work.
• Improving personal ethics and knowing work ethics.
• Being able to do different tasks.

39. 39
Laying of RCC Drainage Gravity Line by
Microtunneling Method

40. 40

41. 41

42. 42

43. 43

44. 44

45. 45

46. 46

47. 47

48. 48

49. 49

50. 50

51. 51