TBM design and specialist tunnelling
equipment procurement
A contractor’s perspective
Chris Moore, Manager, Plant and M&E Services
October 2015
What is Specialist Gear?
TBMs
Slurry
Main Beam Gripper
Earth Pressure
Balance
Double Shield Gripper
Roadheaders
Inline Head
Transverse Head
Drill & Bolting Rigs
Drill Jumbo
Bolting Rig
• Ventilation equipment
• Shotcrete Rigs
• Material transporters (rolling stock, MSV)
• Temporary HV and LV electrical reticulation
• Grouting plants
• Water and ventilation cooling plants
• Lining formworks (water proofing and concrete lining)
• Segment manufacturing facilities
What is Design from a contractor prospective?
• Providing information and design inputs to the equipment manufacturer to enable them to design to:
• Comply with contractor and client specifications.
• Cater for and install temporary and permanent support as specified
by tunnel designers.
• Work within the design limitations of the support design.
• Cater for the operational methods and sequences to be used by the
contractor.
• Be able to work within anticipated tunnel conditions (water inflows, water
quality, ground conditions, ground movement, in tunnel climate).
• To provide a plan B where possible, in the event plan A is not as
successful as anticipated.
Always ensure that the equipment manufacturer is the designer of the Plant
• Ensure safety is always a consideration in all design decisions
Ensure any modifications required on site are designed by the manufacturer or
manufacture checks and verifies modifications the Contractor intends to make.
Interaction of Machine Specification and Tunnel Design:
• Equipment excavation and operating envelopes.
• Support design (Bolts, shotcrete, concrete lining and segment lining).
• Tunnel alignments and drive lengths.
Tunnel Conditions that will influence the Machines Specification:
• Geology (UCS, bedding, features).
• Permissible ground and lining loads.
• Ground water inflows.
• Environmental (outside and within the Tunnel).
• Launch and retrieval sites restrictions.
Machine limitations that can influence tunnel design and sequences of work:
• Cutting profiles and operating envelopes (e.g. drill rigs).
• Machines profiles or dimensions.
• Machine loadings tunnelling walls and linings.
Objectives of machines detailed design decisions when determining machine specification:
• Maximise production and face advance.
• Ability to achieve design alignment (including steering corrections).
• Ensure safety is considered in every design decision.
• Install temporary or permanent support correctly and accurately
Plant design review and inputs
The following are some of the many areas which Contractors need to provide input and
review in order to ensure that the TBM will meet the specifications, tunnel design and
operational requirements of the project.
• Ability to install temporary and permanent support within design tolerances.
• How it caters for materials transport and handling for material
along the TBM and backup.
• Ability and accuracy it can following the tunnel alignment with acceptable
clearances allowing for steering corrections.
• How effectively the TBM will excavate and transport excavated material
from the face.
• How service extensions can be achieved whilst minimizing the
isolation/unserviceability time for the service.
TBM are specifically designed for a job by job basis, most other specialist equipment
such as roadheaders and drill rigs are “off the shelf” with only minor modifications to
their operating envelopes possible. Therefore TBMs will require far more design and
specification scrutiny than other tunnelling plant.
The following are some to the system that should be reviewed by the Contractor
• Cutterhead Design
• Muck handling segments from the cutterhead
• Compressed air and hyperbaric system if applicable
• Main bearing and drive systems
• Rock bolt or segment installation systems as applicable
• Muck haulage along the back up
• Hydraulic systems (suitability, redundancy and isolation)
• Electrical systems (safety devices and isolation)
• Compressed air Systems ( redundancy and isolation)
• Water system – waster water, cooling water, cleaning water
(segregation, accessibility and isolation)
• Ventilation system (adequate air flows and
locations)
• Tunnel services storage and extension (capacities
and accessibilities)
• Fire detection and suppressions systems
• Emergency egress and refuge and applicable
• Systems Isolation and access to all system for
maintenance and repairs requirements
• TBM system monitoring ( gauges, meters PLC,
data logging survey, gas detection etc)
• TBM safety devices, limits, trips, anti collision, guarding,
protection ratings
In all of the above items compliance to standards, codes, legislation, best practices
and above all safety should be considered at all times
• TBM launch and retrieval equipment due to site
access restrictions
• In the case of slurry machines, slurry circuit
design, capacities and limitations
Areas that will be looking into in more details
• Cutterhead Design
• Machine loads on Segmental Lining
• TBM steering
• Backup configuration, traffic envelop limitations and considerations
Examples of design reviews
TBMs
Roadheaders
• Cutterhead selection
• Operating profiles (cutting profiles and machine dimensions)
Bolting Rigs
• Operating profiles (bolt installation profiles and machine dimensions)
Cutterhead design
Face or Gauge
CutterOffset Gauge
CutterTwin Disk
Cutter
Tungsten Carbide
Insert Ring (hard non
abrasive ground
Ripper Teeth (softer
geologies)
Button bit Ring (hard
abrasive ground)
Cutters
GENERAL RATIO OPENNING 42%
Cutterhead configuration
Mono Directional competent
rock
Bi directional mixed ground Bi directional mixed to softer rock
Mono directional heads provide less opening ratio and hence more cutters on the face with less spacing which
in harder rock is a must. Can be an issue for segmentally lined tunnels as TBM and ring roll can be an issue.
Bi directional heads can limit cutter numbers but in softer geologies allows for good material pick up and less
head wear. Also good for correcting TBM and ring roll which can be more likely in softer ground due to high
cutterhead torques.
Cutter head wear protection
Wear Plates
Horizontal wear bars
Vertical wear bars
Horizontal bars prove a better solution when a large amount of fines are produced.
Vertical hoops prove a better solution when a larger rock fragments are produced.
15
Example of cutterhead rim wear
Cutterhead as supplied
Wear suffered
Change to horizontal
bars and the size
required to bring it back
to factory diameter
Repair taking place
16
TBM in foreground being prepared for cutterhead rim repair, TBM in
background nearing completion of repair
Loading of segment by tail skin cylinder pads
Force required = (max load per cutter x no cutters) +(friction force due to TBM weight and backup
towing force if applicable) +( ground pressure if applicable) + (face support pressure if applicable)
TBM max Thrust force is usually > Force Required
Pressure of each pad = TBM Thrust per Cylinder(s) / Pad Area
To minimise pressure per pad
• Maximise pad area (increase segment height or pad length
assuming segment thickness can not be changed)
• Increase number of pads
Which is < permissible load of segment with safety factor
Typical tail skin pad configuration
Large pad sizes = less pads
• Less cylinders in tail skin = good access and more location options to probing holes,
lubrication injection points or tail skin grouting ports.
• Potentially less pads holding segments especially key segments (not advantageous).
• Usually means less chance of pad traversing or contacting too close to a joint.
Smaller pad = greater number of pads
• More cylinders in tail skin = limited access and less location options to probing holes,
lubrication injection points or tail skin grouting ports.
• Usually means greater chance of pad traversing or contacting too close to a joint.
• Potentially more pads holding segments especially key segments (advantageous).
Check pad location to joints
In the above the closest pad location to a joint was segment S3 at 150mm
This example is for a trapezoidal ring configuration and as such has a key and counter
key. In the event that “flipping the ring” is utilized then the counter key contact locations
needs to be analysed.
All ring orientations to be used are to be checked
In the above the closest pad location to a joint was segment S1 at 97mm
Counter Key pad contact locations
Designers should verify that full pad loading at this proximity to a joint will not cause
cracking or failure
Pad contact locations due to ring squatting or arching
Pad width contact
156.5mm & 20mm
clearance to gasket
Pad width contact 153mm
& 4mm clearance to
gasket
Pad contact width
136.5mm & 40mm
clearance to gasket
The location of gaskets and segment face recesses should take into consideration ring
squatting and arching
Tail skin deflection due to external ground loads
Similar calculation should also be done for middle and front shields.
Excessive deflections can induce loading to the ring and induce squatting or arching of ring and
extreme case segment cracking or damage.
Pad contact due to TBM Steering
Contact width =
150mm
Contact width
= 145mm
Contact width =
97mm
Length of tail skin cylinder for traditional Key pull back
Rings with key and counter key
Total cylinder stroke in this case 2800mm
Rings with key and counter key will have longer cylinder pull backs than traditional single key
arrangement. This will increase the length of the Tail skin and hence may affect the steering radius to
the TBM
Shield clearance at tunnel design alignment
13 mm
0 mm
6 mm
-9 mm
Shield clearance at TBM Steering capability
20 mm
5 mm
Solution in this case – shim out gauge cutters or use oversize rings
6660 -> 6688 mm
6630 -> 6658 mm
In soft geologies copy cutters could be used to achieve overcut. In harder geologies
the use of reamer disk cutters is not recommended
Backup configuration, traffic envelop limitations and considerations
Traffic envelops – Rolling Stock materials haulage (gradients up to 3-4%)
Rolling stock running on back deck – very
stable no misalignment of rolling stock
and back up. Usually only possible on
larger diameter TBMs. Demob backwards
easier (multiple decks at a time may be
possible)
Rolling stock and back up using same
sleeper – very stable, back up rail
usually leap frogged. Backwards demob
of back up may need extra rail or via
heavy duty flat car (one deck at a time).
Rolling stock fixed on rails – backup
can roll – back up bogies should be
steerable. Backwards demob easier
(multiple decks at a time may be
possible).
MSV and back up can roll
independently. Backward
demobilisation of back up easier
(multiple decks at a time might be
possible)
Traffic envelops – MSV materials haulage (any gradient)
Backup fixed but MSV can roll.
Backward demob of back up may need
extra rail or use MSV as carrier (single
deck at a time)
0o tilt 1.3o tilt 4o tilt
Back up roll considerations
Note in the above scenarios the MSV can steer and induce a tilt therefore load stability on an angle needs to be considered
Backup traffic envelop to negotiate tunnel alignment
Backup deflections due to internal loads
Back up structure deflections will decrease back up traffic envelop
35
Roadheaders
• Mistui - Japan
• Sandvik - Austria
• BBM - Germany
• Sanyi - China
• NHI - China
• CCTEG - China
• MHWirth (Paurat) – Germany (China)
• Kopeysk - Russia
• Kopex - Poland
• Eickhoff - Germany
Major Manufacturers
• Mistui - Japan
• Dosco – United Kingdom
• And others
Roadheaders
Inline Heads Transverse heads
• Better in softer geologiesMore suited to harder Geologies >50MPa
Some manufacturers provide head option
for different rock strengths (varying
number of picks, the more picks the
harder the geology that can be cut
efficiently)
Machine dimension and cut profiles
300kW class
Profile#1 Arch Roof straight walls
Planned bench height shown as dotted
line
39
Profile#1 Arch Roof straight walls
Two typical Roadheader models one
with a high cut
40
Profile#1 Arch Roof straight walls
The models provide an option to lower
the bench height, one can do full face.
41
Profile#1 Arch Roof straight walls
Consider a machine that cuts lower and
has a lower machine dimension
42
Profile#1 Arch Roof straight walls
Capability to decrease heading size
and hence face advance will be
increased
Profile#2 – Fully Arched
Planned bench height shown as dotted
line
44
Profile#2 – Fully Arched
Two typical models positioned on preferred
bench height
Can not reach
this area
45
Profile#2 – Fully Arched
Drop the bench height, model on
the left could offer a full face cut
option
This area can not be reached would need
a three locations cutting sequence
46
Profile#2 – Fully Arched
Select a different model with a wider cut but in
this case a full face cut is not possible
Bench height with previous
Models
New Bench Height
Profile 3 – Cavern Machine multiple Relocation
Planned bench height shown as dotted
line
48
Profile 3 – Cavern Machine multiple Relocation
Roadheader location required to cut the
bottom corner
49
Profile 3 – Cavern Machine multiple Relocation
Four relocation require to cut the full
width
Location of roadheader too close to crown for safe operation but
positioning it further to the centreline will mean the bottom corners can not
be reached.
50
Profile 3 – Cavern Machine multiple Relocation
Lower the height of the bench to get
clearance to the machine
51
Profile 3 – Cavern Machine multiple Relocation
Consider a machine with a wider cut
52
Profile 3 – Cavern Machine multiple Relocation
The scenario only requires three relocations but the
ability to cut a lower bench is not possible
53
Profile 3 – Cavern Machine multiple Relocation
Consider a machine with a higher cut
54
Profile 3 – Cavern Machine multiple Relocation
Four relocations required but….
55
Profile 3 – Cavern Machine multiple Relocation
Almost a full face excavation can be
achieved if required
56
Roof Bolters
• Robodrill - France
• Atlas Copco - Sweden
• Sandvik - Finland
• Fletcher - USA
• Caterpillar - USA
• Joy - USA
• Mine Master - Poland
• MacLean Engineering - Canada
• Prarie Machinery - Canada
• And others
Profile#1 Arch Roof straight walls
58
Bolter mast height depicts 4.5m
(end to end) length bolt.
Centre bolt pose no issue
59
Bolter mast height depicts 4.5m
(end to end) length bolt.
The side bolts will
require the bench to be
lowered
Combine Roadheader and Bolter solution
Found potential to make
bench higherRoof Bolters are likely to
influence bench height
Preferred machine
Profile#2 – Fully Arched
Bolter mast height depicts 4.5m
(end to end) length bolt.
Combine Roadheader and Bolter solution
Preferred machine Shoulder bolts dedicate
bench heightAlternative machine model could
be considered centre crown
excavation could be an issue (ie
relocations will increase)
Obviously Roadheader model and bolt length set up should be selected the most common heading
size and shape and support lengths.
Consider obtaining design approval to install limited number of crown bolts
during heading excavation and the remainder at bench excavation to raise
bench.
Also obtaining design approval to lower the angle of some of the shoulder bolts to
raise the bench height
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