CITY EAST CABLE TUNNEL
WEST TO EAST CONTINUOUS IMPROVEMENT FROM
CITY WEST TO CITY EAST CABLE TUNNEL
The 12th Australian Tunnelling Conference 21st November, 2013
Christian D’Hondt (Thiess) | Tim Burns (Thiess)
• Early contractor involvement (ECI)
• Flexural strength assessment of SFRC segments
• Backfill of segment lining annulus
• Cast in-situ lining
• Separation of plant and pedestrians
• TBM specification
CONTINUOUS IMPROVEMENT
AUSGRID’S SYDNEY CITYGRID PROJECT
CITY WEST CABLE TUNNEL
• 2007 – 2010 Completed & operational
CITY EAST CABLE TUNNEL
• 2011-2015 Under construction
• Constructability advice to client and designer
• Imputing into value engineering workshops
• Generating construction programs
• Advice and input into the environmental assessment
• Providing cost estimates at various stages of the development of the design.
EARLY CONTRACTOR INVOLVEMENT
(ECI)
• CWCT project, flexural beams (ASTM C1609)
• Co-efficient of variation for residual flexural strength 29.4%.
• CECT project, supersized round panels (ASTM c1550)
• Co-efficient of variation of super-size round panel residual flexural strength 10.9%
CONTINUOUS IMPROVEMENT
FLEXURAL STRENGTH ASSESSMENT OF SFRC
SEGMENTS
Residual Flexural Strength Spread at CWCT
Residual Flexural Strength Spread at CECT
• Open mode hard rock TBM
• A two component A / B annulus grout
• Injected through tail-shield grouting ports directly into the annulus.
• Inject the B component into the a component stream inside the tail-shield as opposed to in the annulus
CONTINUOUS IMPROVEMENT
BACKFILLING OF SEGMENT LINING
ANNULUS
• Horizontal crown with curved chamfers
• Bespoke steel shutter was made to form the curved obvert
• Wall pours separate to crown pours
• Heavy steel shutter in tight workspace
• Average productivity of 0.55m/day
CONTINUOUS IMPROVEMENT
CAST IN-SITU LINING
• Horizontal crown with two 45 degree chamfers
• Standard formwork components
• Allowed integrated wall and crown pour
• Lighter more manageable components
• Average productivity of 1.47m/day (167% IMPROVEMENT)
CONTINUOUS IMPROVEMENT
CAST IN-SITU LINING
Key control - physically separate plant movement from pedestrian movements
• 1000 semi trailers
• 5000 truck & dogs
Constrained CBD site
Pedestrian bridge and elevated walkway
Spoil loading inside acoustic shed to separate from public
CONTINUOUS IMPROVEMENT
SEPARATION OF PLANT AND PEDESTRIANS
• Offset TBM backup
• Reduced need for persons to enter the rail envelope
• Access, control and maintenance of all devices from walkway
• Beneficial for shaft launch
• Integral with TBM design
CONTINUOUS IMPROVEMENT
SEPARATION OF PLANT AND PEDESTRIANS
Cutter head
• Mono directional
• Openings 15%
• 17” cutters
• Inclined loading plates
Erector
• 6 degrees of functionality
• Vacuum erector
Dewater
• Hydraulically removable dewater tank
CONTINUOUS IMPROVEMENT
TBM SPECIFICATION
WEST TO EAST
Continuous improvement from city west to city east cable tunnel
Acknowledgements:
• Ausgrid
• Structural concrete industries (SCI)
• SMEC
• Caterpillar tunnelling Canada
• Tachibana material co.
CONTINUOUS IMPROVEMENT
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