Trenchless Technology - CEDD

Trenchless Technology

Adopting Rectangular TBM for Tunnel & Pedestrian Subway Construction

Shanghai Tunnel Engineering Co. Pte Ltd

Innotech Forum on Geotechnology

The Machine

• EPBM with rectangular

geometry

• Commonly used for the

construction of underground

pedestrian subways and metro

lines

• Since 2015, more than 10 such

RTBM projects have been

completed


Rectangular TBMs/PJMs can be used for the construction of road tunnels,

underground pedestrian subways, and even metro lines where the overburden

is relatively shallow.

Road Tunnel Pedestrian Subway Metro Line

Applications


ECC Cutter(Auxiliary

Cutter)

Main Cutter

ECC Cutter Drive(Auxiliary Cutter

Drive)Main Drive

Screw Conveyor

Articulation Jacks Thrust Ring

U-Ring

Thrust Block

Thrust Jack Frame

Cradle

Tail ShieldFront Shield 2Front Shield 1

RTBM Components


Pipe Jack vs

Thrust Boring


RectangularPipe Jacking Machine (PJM)

Circular Earth Pressure Balance Machine

(EPBM)

RPJM vs EPBM Thrust Boring


AspectComparison

Rectangular PJM Circular EPBM

Thrust / Jacking

Force

Added weight of segment + skin

friction-

Geometrical

propertiesSusceptible to warping deformation

Uniform stress distribution; better load

bearing capability

Precast Elements Monolithic Segments form up a ring

Waterproofing Gaskets Gaskets

Pipejacking Thrust Boring

Thrust

System

Thrust

System

Tunnel Lining Design


AspectComparison

Rectangular PJM Circular EPBM

Machine Cost Relatively cheaper Cost more

Site Utilization Less demanding (20-30% of TBM) Relatively demanding (Large)

Settlement

ControlVery good (Overcut = Annulus)

Overcut + Shield Annulus +

Tail Skin Gap

Alignment Straight Curvature

Excavation Cycle

Time4 – 12 hours 1 – 4 hours

PJM Site Setup TBM Site Setup

Cost, Productivity, Safety, & Efficiency


AspectComparison

Rectangular PJM/EPBM Circular PJM/EPBM

Tunnel Space

Utilization

More efficient use of space

Approximately 35% more dead space

and 30% more excavated material

Finishing Works MinimalAdditional backfilling works required,

intermediate first stage concrete

For the same tunnel internal clearance requirements (e.g. 2100mm by 2000mm):

Space Utilisation and Finishing Works


AspectComparison

Rectangular PJM Circular TBM

Ground

Conditions

Not suitable for hard ground, mixed

ground, and bouldersAny type

Cutterhead

InterventionsDependent on machine size Normally possible

Cutter ChangeCutter change not required for short

tunnel drives

Must be designed to accommodate

cutter change

Tunnel AlignmentShort and straight, intermediate

jacking stations may be requiredCan be designed for most alignments

Overburden Generally shallow Deep

Technical Comparison


AspectComparison

Rectangular PJM Circular TBM

Costs Lower Higher

Site setup Simple Complicated

Tunnel Alignment Short and straightCan be designed to any length and

suitable curvature

Tunnel space

utilizationEfficient Dead space present

GeologyIdeally soft homogeneous ground with

shallow overburdenAny

Design More considerations and constraintsVersatile in design to suit varying

conditions

In summary, the rectangular PJM as a method of construction will outshine the TBM

in projects where:

1. Soft, homogeneous ground with relatively shallow overburden

2. Short and straight alignment

3. Site space constraint

Summary


Notable Projects

&

Innovations


Funan UPL, Singapore UPL, Zheng Zhou KT3B, Hong Kong

Mac

hin

e U

sed

Co

ntr

act

Info

rmat

ion Underground Pedestrian Linkway

Tunnel length – 105mInternal dimension – 6.6 x 4.8mAdvance rate – 1.5m/dayOverburden – 4m to 6m

Underground Pedestrian LinkwayTunnel length – 183mInternal dimension – 9 x 6.1m &;Internal dimension – 6 x 3mAdvance rate – 1.5m/dayOverburden – 4m to 6m

Underground Pedestrian LinkwayTunnel length – 148mInternal dimension – 3.9 x 2.8mAdvance rate – 2.5m/dayOverburden – 6.6m to 9m

Soil

Co

nd

itio

ns

Predominantly marine clay Predominantly silt and silty clay Predominantly fill, colluvium & alluvium

Notable Projects


Steel Segments

For large dimension rectangular tunnelling

projects, the use of reinforced concrete tunnel

segment linings might not be practical due to

its mass.

Steel segments can be fabricated off-site and

delivered to site for assembly and tunnel

construction.

Segment Tipping Frame

Segment Turning Device

Other Innovations


Hong Kong

Projects


The RTBM was launched from Shing

Kai Road, and then dismantled and

removed from the retrieval shaft at Choi

Hung Estate.

RTBM Parameters

Shield Type EPB

Excavation

Dimensions5020mm x 4020mm

Max Thrust Speed 50mm/min

Max Total Thrust

Force36000 kN

Total Power 518 kW

Rated Torque 1287 kNm

Segment Specifications

Segment Outer

Dimension

5000mm x

4000mm

Width 1500mm

Thickness 500mm/600mm

Design Life 120 Years

Design Strength 60 MPa

Segment Inner

Dimension4000mmx2900mm

Contract KT3B – Project Introduction

Kai Tak Development – Stage 3B

Infrastructure at Former North Apron

Area


Challenges Description

Varying Ground

ConditionsVarying ground conditions along the planned tunnel alignment

Shallow OverburdenShallow overburden poses significant engineering challenges, especially in soft/fill

ground conditions

Under-crossing

Existing Structures &

Road

The tunnel alignment under-crosses Shing Kai Road, elevated Kwun Tong Bypass

expressway, 4-lane Prince Edward Road East, & an existing 4-cell box culvert

Under-crossing

Existing Underground

Utilities

The RTBM under-crosses many existing utilities such as the 400kV & 132kV power

cables, telecommunication lines, gas pipes, pipes for the district cooling system,

sewage pipes, drainage pipes, and water mains

Contract KT3B – Challenges


Contract KT3B – Milestones & Activities

RTBM FAT Tunnel Construction RTBM Breakout

Replacement Grouting RTBM Disassembly Completion of Tunnel


Advantages TBM Tunnelling

Productivity Approximately 30% increase in productivity

Engineering Safety Better control of soil movement and ground settlement

Construction Safety Workers physically shielded from the soil face

Quality Control Precast elements used

Environmental Control Lower noise/dust production

Diversion Works Significantly less traffic and utility diversion works

Contract KT3B – Advantages of RTBM


Upcoming Project – KT5B

Construction of an underground pedestrian subway across PERE between Kai

Tak Area and Sa Po Road (Kowloon City).

Conforming Design(cast in-situ concrete lining)

Proposed Design (CSD)(realigned and constructed using RTBM)



Feasibility of Trenchless Excavation Method over Open-cut Method

• High traffic volume along PERE makes trenchless excavation method of construction more favourable for SB-01 construction

• Traffic diversion works can be avoided

• Utility diversion works can be avoided since RTBM will go underneath the existing utilities

• Lower impact to surrounding structures due to better settlement control

• Successful construction of KT3B underground subway on 02 Oct 2020 using the same method



RTBM and Segment Design RTBM Parameters

Shield Type EPB

Excavation

Dimensions

10830mm x

7530mm

Max Thrust Speed 40mm/min

Max Total Thrust

Force65000 kN

Total Power 1000 kW

Rated Torque 2500 kNm

Segment Specifications

Segment Outer

Dimension

10800mm x

7500mm

Width 1500mm

Thickness 700mm

Design Life 120 Years

Design Strength 60 MPa

Segment Inner

Dimension

9400mm x

6100mm


RTBM Track

Records


Year 1995 – First

Generation

2.5m × 2.5m Variable

Grid Rectangular

Shield

Year 1999 – Second

Generation

3.8m × 3.8m

Rectangular Shield

Equipped with

Cutterhead

Year 2003 – Third

Generation

4m × 6m Rectangular

Shield with Eccentric

Rotation Cutterhead

Year 2011 – Fourth

Generation

4.2m × 6.9m Rectangular

Shield with General and

Eccentric Rotation

Cutterhead

Year 2013 – Larger

Machine (4th Gen)


Shield with Combination of

Circular and Eccentric

Rotation Cutterhead

Year 2017 – Fourth

Generation


Shield with 9 nos. of multi-

layer cutterhead

Tim

elin

e

Tim

elin

e

Evolution of the RTBM


7.5m x 10.4m `

6m x 9m

7.6m x 6.4m

4.2m x 6.9m

4m x 6m

2002

Kun Shan Underpass

1999 2004

3.8m x 3.8m Shanghai Sewer Shanghai Metro

1995

2.5m x 2.5m Shanghai Sewer

0

1995 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 On-going (Years)

2.5x2.5m Year 1995

3.8x3.8m Year 1999

Second Generation

Third Generation

4x6m Year 2003

TREND CHART OF RECTANGULAR TBM (From 1995 to Present)

First GenerationRectangular TBM

LEGEND

(Dimensions)

Square TBM

Fifth Generation

7.5x10.4m Year 2012

Fouth Generation

4.2x6.9m Year 2011

2005Ningbo Underpass

2003Shanghai Sewer

2009Shanghai Underpass

2007Shanghai Conduit

2006Shanghai Metro

2006Shanghai Metro

2008Shanghai Metro

2008Shanghai Metro


2008Shanghai Metro

2008Shanghai Metro

2009Nanjing Metro

2009Nanjing Metro

2010Nanjing Underpass

2010Nanjing Underpass

2010Shanghai Metro

2009Nanjing Metro

2011Wuhan Metro

2003Shanghai Sewer

2007Shanghai Metro

2007Shanghai Metro


2009Shanghai Metro

2010Zhejiang Underpass

2011Zhejiang Underpass

2012Shanghai Metro

2013Shanghai Metro

2013Zhenzhou Metro

2014Shanghai Metro

2014Nantong Metro

2014Ningbo Underpass

2016Zhengzhou Underpass



On-goingShanghai San Men Rd Underpass

On-goingShanghai Jin An Temple

On-goingSingapore Funan UPL

Summary

Total Rectangular Tunnel Projects: >40

Our Track Records

THANK YOU

Shanghai Tunnel Engineering Co. Pte Ltd

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Trenchless Technology - CEDD