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