Tunnel-boring machines are the primary gear for the development of trenchless underground designing tasks, for example, rail travel, civil designing, railroad tunnels, and so on. This paper reviews various tunnel boring machine types, cutting tools, and machine performance through several case studies.

1. Performance review of Tunnel Boring Machines
TBM
Abstract— Tunnel-boring machines are the primary gear for
the development of trenchless underground designing tasks, for
example, rail travel, civil designing, railroad tunnels, and so on.
This paper reviews various tunnel boring machine types, cutting
tools, and machine performance through several case studies. It
was found that these machines are highly efficient in various
projects associated with hydropower, sewerage, water supply,
irrigation, and transportation. The idea of the ground conditions
decides the decision and situating of the unearthing apparatuses for
the shaper head or the cutting wheel. Just if the apparatuses are
consummately coordinated to the topography, the TBM can
accomplish high tunneling exhibitions. It was also noted that the
machine performance depends on the change of uniaxial
compressive strength of soil in a variety of geological rock
compositions and underground water reservoirs.
Keywords— TBM, UCS, Tunnel, Boring.
1. INTRODUCTION
The bore development technique for burrows incorporates
tunneling a chamber-like section through the earth. This is
usually applicable for mountain tunneling, tunneling under
bodies of water for various purposes like transportation and
other supply lines. Maybe than traditional tunneling
techniques which widely use explosives and difficult work,
motorized tunnel unearthing is finished by Tunnel Boring
Machine (TBM). The rotating cutter head thrusts into the rock
surface from the front, from that the surface of the rock
breaks. With the help of anchoring the grippers develop the
reaction to apply thrust and torque forces. Tunneling with it is
considerably more proficient and results in abbreviated
consummation times, expecting they work effectively. The
Double shield tunnel boring machine used in subsurface
mining has been shown in Fig. 1. The best strategy for
working through intensely broke and sheared rock layers is the
drilling and blasting technique. A typical TBM includes a
hydraulic thrust system, and an attitude positioning system.
The cutter head system undertakes the task of excavating
rocks and soil, which plays an important role[1].
Figure 1. Double Shield Tunnel boring machine used in
subsurface mining
The technologies of the Double-O-tube (DOT) and Multi-
circular Face (MF) shield machines (Fig. 2(a) and (b)) were
mainly developed in Japan [2]. Contrasted and an equal twin
passage, the width of a cross-segment exhumed by a DOT
safeguard machine is much smaller, to be for the most part
applied to the incorporated removal of tram stations. In any
case, inferable from the intricate removal cross-areas and
generally enormous ground aggravation soil can cling to the
TBM safeguard body and amass during TBM progression. By
expanding the unconventional multi-shaft cutter head a quasi-
rectangular TBM was created dependent on the DOT
safeguard machine. The removal cross-segment, whose upper
and base shapes are roundabout curves, has an oval-like semi-
rectangular shape that has improved the bearing limit of the
gear and sections, tackled the dirt issues, and decreased
ground unsettling influence (Fig. 2(c)).
a b c
Figure 2. (a) DOT shield machine; (b) quasi-rectangular
shield machinery; (c) MF shield machine
The burrowing execution and the financial effectiveness of
motorized burrowing are affected by the quality and the
lifetime of the unearthing instruments. The high material
nature of the apparatuses guarantees the useful evacuation of
soil or rock from one viewpoint, and low personal times
because of high toughness on the other. The exhuming
instruments are introduced on the shaper head – in the delicate
ground called the cutting wheel. With the assistance of
rotational development of the shaper head and the push of the
water-powered jacking stations, loses the stone and the dirt at
the passage face by uncovering devices. Contingent upon the
topography, the shaper head is outfitted with cutting blades
and plate cutters or rippers. To guarantee that a task stays
inside the determined financial plan, additionally concerning
tooling, the exhuming apparatuses should proceed as gauge
even with incredibly high stone qualities, scraped area, and
water compulsion.
2. OPERATING PARAMETERS OF A TUNNEL BORING
MACHINE
2.1 PARAMETERS FOR SELECTING TBM TYPES
Tunnel Boring Machine incorporates complex sorts of
hardware for exhuming burrows with the assistance of an
assortment of soil and rock layers. In 20 hours per day the

2. machine approximately excavates around a average of 50 to
60 feet [3]. The best machine for an undertaking is chosen
based on the land states of the site. A standard specification of
double shield TBM machine is shown in Table 1 to get a fare
idea of cutting parameters.
Table 1. Specification of Double shield TBM [3]
Parameters Value Parameters Value
Machine diameter 4.65m Cutter head
power
5 x 250 =
1.250 KW
Cutter diameter 432
mm
Cutter head
speed
0-11 rpm
Numbers of disc
cutters
31 Cutter head
torque
1723 KNm
Disc nominal
spacing
90 mm Conveyor
capacity
200 m3/hr
Maximum
operating cutter
head thrust
16913
KN
TBM weight 170 ns
Essentially, it tends to be ordered into eight sorts relying upon
both hard rock and delicate ground. Gripper type is suitable
for driving in hard rock conditions when there is no
prerequisite for the last covering. For hard rock burrows, the
Double-safeguard type is by and large viewed as the quickest
machine. For the dirt which doesn't bear groundwater and
where rock conditions are less the Single-safeguard machine is
utilized . Earth pressure balance advancement is suitable for
plunging tunnels in the shaky ground like mud, buildup, sand,
or rock. The slurry is utilized for exceptionally flimsy and
sandy soil. Blend safeguard innovation is a variation of
ordinary innovation for heterogeneous geographies and high-
water pressure. Line jacking additionally called miniature
burrowing to limited scope burrowing strategy for introducing
underground pipelines with the least surface interruption.
Incomplete face exhuming machines have an open-face
protection and can once in a while be more practical.
2.2 Parameters involved in the selection of Cutting
Wheel and Cutter head
The nature of the ground conditions determines the choice
and positioning of the excavation tools for the cutter head or
the cutting wheel. Just if the apparatuses are consummately
coordinated to the topography, the TBM can accomplish high
burrowing exhibitions. However, the respective ground
conditions challenge their liability of the tools in different
places. In delicate soils, insurances should be taken to prevent
the circle cutters from getting obstructed. In excavation in
granite, the disc cutters must pass the absolute hardness test.
When choosing the appropriate tool size limited space at the
cutter head and the maximum possible load on the disc cutter
bearings are also crucial factors. A wide scope of cutting
blades, containers, rippers, and different apparatuses
supplement the range for activities in free soils. Regarding
these kinds of devices, the strength and material arrangement
are additionally key factors in streamlining time and expenses.
The solidness of the uncovering apparatus edges and
additionally teeth is improved hugely by welding carbide
metal – tungsten carbide. Contingent upon the topography,
cutting blades, cans and rippers are given a welded hard-
looking on the instrument body to ensure it against grating soil
glue. [4] The high-compound device steel of the cutting ring
should not exclusively be difficult to oppose wear, the
material sturdiness is additionally a significant factor for its
lifetime. Unnecessarily fragile steel would prompt early
material spalling at the cutting ring during rock explodes,
which happens sometimes. Exhuming apparatuses up to 8
creeps for more modest unearthing measurements are likewise
made of high-compound device steel. Various types of disc
cutters, their operational orientation, and cutter head
geometries have been shown in Figure 3.
A
B
C
Figure 3. (a) Disc Cutter Size and types (b) Cutter Placement
on TBM shield, (c) Geometry of Cutter Heads
At the point when the pivoting cutting wheel on the TBM
head is pushed forward against the passage face, cutting
devices mounted on the shaper head are in touch with the
ground and are subsequently dependent upon constant wear
measures. This wear conduct of the slicing apparatuses is
profoundly identified with earth pressing factor or
abrasiveness and machine directing boundaries, for example,
the face support pressure,progressed speed, and cutting wheel
turn speed. At whatever point a device arrives at a basic wear
level and should be supplanted, the creation cycles of the
TBM should stop to gain admittance to the exhuming chamber
and to the cutting wheel. Temperamental ground conditions
require a compressed exhuming chamber to forestall a
breakdown of the passage face. Delivering the help pressing
factor and leading support work in environmental pressing
factor conditions altogether builds the dangerof a passage face
breakdown and is for the most part unworkable. When
working under compressed conditions, extra time is required
for laborers to adjust to compressed conditions. Therefore,
support work is an intricate and tedious interaction altogether
diminishing the presentation, however fundamental to
guarantee the usefulness of the TBM. A support method for

3. TBM cutting apparatuses can be isolated into the activation
cycles, review and instrument supplanting work, and the
deactivation measures [5]. The time needed for mobilization
procedure (tmob) incorporates the ideal opportunity for bringing
down the level of support (tlow), compressing workers
(tcompress), installing working platforms (tinstallation), and cleaning
the cutting wheel (tcleaning).
3. Case Studies on TBM performance and
Parametric Effects
3.1 Subsurface System Tunneling
Change of all surface water pipelines and to make subsurface
frameworks by building passages to stay away from issues of
spillage, flighty misfortune and furthermore to shield water
from contamination.[6] To improve the water supply to
Vakola, a 12.24 km long passage between Maroshi and
Ruparel College was uncovered by a Tunnel exhausting
machine. The tunnel is separated into three segments,
i.e.Maroshi–Vakola(5.834 km long), Vakola–Mahim(4.549
km), and Mahim–Ruparel College(1.859 km) (Fig. 4).
Development for burrows from Maroshi to the vent opening
and from Vakola to the vent opening, vertical shafts were built
at one or the flip side. The channel shafts of 82.0 m and 68.0
m top to bottom from ground level, 9.0 m in breadth. On the
contrary side along with the passage pivot, two 50 m long tail
burrows were additionally exhumed to work with refuse
vehicle development while dumping [7].
Figure 4. Longitudinal section and plan of tunnel from
Maroshi to Ruparel College [7]
TBM execution of Maroshi–vent opening and Vakola–vent
opening passages are displayed in Table 2. Studies indicate
that in Deccan traps, varieties in rock types, flow contacts,
rock strength, and volumetric joint sum with the presence of
frail zones have dominatingly influenced the infiltration rate
and steadiness of passages. [3]. It had been all around
perceived that joints or cracks importantly affect the machine
execution. Based on countless contextual analyses, it
presumed that with the lessening of joint dispersing, the TBM
entrance increments particularly[8]-[10]. The greatest
infiltration rate was recorded for a point of 60°. It was
additionally noticed that with the expansion of joint
separating, the impact of joint direction diminishes.
Table 2.TBM performance in Maroshi–vent hole and Vakola–
vent hole tunnels. [7]
3.2 Large Tunnel Excavation with TBM under-passing
two highway Tunnels
It manages the presentation of the Tunnel Boring Machine
(TBM) settled on the development of the Interstate Raw Water
Transfer (ISRWT) project right now built-in Selangor-Pahang,
Malaysia. In this undertaking, the 44 km Interstate Raw Water
Transfer burrow is intended to cross strong stone along with
the arrangement with the overburden at different focuses.
Considering the land state of the proposed arrangement like
the hard rock of Titiwangsa Main Range Granite, open sort
TBM was chosen [11]. The assessment of the performance of
TBM depends on boundaries like exhausting energy, rate of
penetration (ROP), and rate per minute (RPM). Three diverse
information from the tunnel site have been accounted for in
the writing, the day-by-day tunnel planning record, the TBM
execution information, and lab test consequences of Uniaxial
Compressive Strength (UCS) on rock tests at every 50 m of
the tunnel. The day-by-day planning recorded the strength of
unblemished stone, joints properties, and groundwater
conditions. The 'UCS/SHR value' was gotten from the
Schmidt Hammer Rebound (SHR) test while 'UCS rock core'
was acquired from testing new rocks of each 10 m cut-off in a
non-brokenness region. Three-block tests (A, B, and C) from
the high groundwater inflow region were tried for UCS (Dry
and Wet). Table 3 shows the aftereffects of the Uniaxial
Strength Test for dry and wet examples individually.
Table 3.UCS result for dry and wet rock specimens
Dry / Wet Specimens UCS (MPa), Young's Modulus
Dry AD1 176.048 56.875
Wet AW8 69.761 31.674
Dry BD1 132.129 56.525
Wet BW5 52.354 62.272
Dry CD1 246.981 82.106
Wet CW3 123.566 52.431
The two tests showed a palatable connection as the bounce-
back hardness esteems diminished with the diminishing worth
of UCS. It shows that the strength of rock diminished or
getting less, over half from its dry worth when it is wet.
Scarcely any troublesome unearthing by the TBM were
visualized because of the presence of issue zones, high
overburden, and possible danger of intersection water-bearing
zones. In one of the areas, 10 ton/min of unexpected inrush
warm water experienced where TBM recorded 46.50 N/mm2
of boring energy, 7.10 fire up/min of RPM, and 0.80 m/h of
ROP. Due to these reasons, a slight drop in boring energy and
daily progress was recorded. It was noted from reports that at
explicit areas high-grade rock required a high kind of
emotionally supportive network in view of the presence of a
sheared zone of new stone. Boring energy was found low due
Tunnels Tunnel
boring
length
(m)
Shape Excavated
diameter
(bore
section)
(m)
Finish
ed
diame
ter
(m)
Excavat
ion
quantity
(m3
/m)
Volume
(totalexc
avation)
(m3
)
Maroshi–
vent hole
3086.34 Circula
r
3.6 3.0 10.18 31,419
Vakola–
vent hole
2590.4 Circula
r
3.6 3.0 10.18 26,370

4. to the presence of favorable fracture orientation. At certain
spots, the water entrance was exceptionally high at in excess
of 300 liters/min which debilitated the stone into more modest
pieces and caused higher exhuming progress each day.
3.3 Case Study from Deccan Traps, India
In this investigation, an endeavor has been made to set up the
connection between rock mass qualities, UCS of the Deccan
trap rocks, and TBM execution. Studies show that the
infiltration rate diminishes with an increment in uniaxial
compressive strength. The correlation of estimated entrance
rate with the observational model created by Graham, in
which, the infiltration rate is figured utilizing this and normal
push per shaper, showed great concurrence with a coefficient
of assurance [13,14]. The assessment shows that the TBM
execution was generally outrageous in rock mass rating
(RMR) range from 40 to 75, while all the more sluggish
penetration was recorded both in particularly poor and by and
large magnificent stone masses. It is notable that Deccan
volcanic cover an immense space of almost 500,000 km2 of
the Indian subcontinent and achieve a thickness of 1.6 km
above. It was broadly jointed and given stable ground
conditions to burrowing. Because of its underlying and
textural variety, the UCS of the unblemished basalts changed
from 33.35 MPa to 143.33 MPa, and the stone mass falls
under reasonable for great rock mass classes. [15]. The stone
breakage measure is firmly identified with the machine
boundaries, like TBM distance across, shaper line dividing,
shaper breadth, tip width, greatest RPM, complete push, and
force. The exhausting time cycle subtleties concerning
worldwide standards are given in Fig. 5. The level of
compaction and grain size additionally differ in the top, center,
and base segments of each stream, due to these there is no
direct relationship found among RMR and TBM infiltration
rates.
4. Acknowledgment
I wish to communicate my significant and earnest
appreciation. Dr. Sandip Ghosh (Assistant Professor, HOD of
Mechanical Department, JIS College of Engineering) for his
recommendation, oversight, and the fundamental commitment
as and when needed during this examination. His inclusion
with innovation has set off and sustained the scholarly
development that will help me for quite a while to come. I'm
glad to record that I had the chance to work with an
uncommonly experienced educator like him.
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Figure 5: Boring time cycle details with respect to
international norms [15]