Chris Moore - John Holland - TBM design and specialist tunnelling equipment procurement - A contractor’s perspective

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


Two typical Roadheader models one

with a high cut

40


The models provide an option to lower

the bench height, one can do full face.

41


Consider a machine that cuts lower and

has a lower machine dimension

42


Capability to decrease heading size

and hence face advance will be

increased

Profile#2 – Fully Arched


line

44


Two typical models positioned on preferred

bench height

Can not reach

this area

45


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


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


line

48


Roadheader location required to cut the

bottom corner

49


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


Lower the height of the bench to get

clearance to the machine

51


Consider a machine with a wider cut

52


The scenario only requires three relocations but the

ability to cut a lower bench is not possible

53


Consider a machine with a higher cut

54


Four relocations required but….

55


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


58

Bolter mast height depicts 4.5m

(end to end) length bolt.

Centre bolt pose no issue

59



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




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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Chris Moore - John Holland - TBM design and specialist tunnelling equipment procurement - A contractor’s perspective