daniel clert - bouygues construction - north strathfield rail underpass
TRANSCRIPT
Sydney – 14th October 2015
Daniel Clert
North Strathfield Rail Underpass Shallow tunnelling techniques
Northern Sydney Freight
Corridor (NSFC) Program• Remove bottlenecks
and enhance freight
capacity, availability,
reliability and journey
time
• Includes grade
separation, track
amplification and
passing loops2
North Strathfield Rail
Underpass
3
Current
at-grade
crossing
Project scope
4
Delivery partners
Investigations and geotech
Concept design
Detailed Design
5
Review of Environmental
Factors
Signalling concept
Detailed design
6
• Underpass ~ 148m long
Overview
7
2.8% slope on approach2.1% slope on exit
Shallow Cover
Indicative Geological Profile
Siltstone,
Ashfield Shale
Formation
Weathered Shale
Shallow driven tunnel
Ballast and sub-base
Stiff Clay
Tunnel Support
Observation on site: For 6 Mpa: Best case 6hrs, Worst case 12hrs, average 7hrs
Main Options taken:
- Full face excavation.
- Fast Setting (accelerated) Shotcrete
(5% accelerator).
- Permanent Monitoring (survey and
shotcrete).
- Close proximity between Design,
Methodology and Construction teams.
Support Contingency – Lattice Girders
Support Contingency – Steel Sets
Methodology
Surface Layout
19
Overview
Materials: Canopy tubes
Face nails (Face and wall stability)
Cycle Times for a 1.3 m advance
• CANOPY TUBES 2.00 days
• CUT & SC 1 0.85 day
• CUT & SC 2 0.85 day
• CUT & SC 3 0.85 day
• FACE SUPPORT 1.00 day
• CUT & SC 5 0.85 day
• CUT & SC 6 0.85 day
• CUT & SC 7 0.85 day
• CUT & SC 8 0.85 day
• SUB-TOTAL 8.95 days
Progress
The NSRU project was commissioned in June 2015.
5 months ahead of schedule
Tunnel Progress on NSRU
Permit to Tunnel
• Permit to Tunnel issued every 24 hours.
• PTT includes review and analysis of:
• Face Mapping
• Track and Surface monitoring
• In tunnel: Convergence monitoring
• PTT confirms all support from previous 24 hours
installed.
• PTT instructs support requirements for next 24
hours.
Supported Ground: Safety aspects
• No Access under ground that does not have as a
minimum:– Canopy Tubes
– 150mm Shotcrete at 1MPa or greater
• Exclusion zone around the face unless there is as
a minimum:– Face dowels
– 50mm Shotcrete on the face
• No access under shotcrete until it reaches 1MPa.
Shotcrete testing in the tunnel
Verification of 6 Mpa strength with Beam end testing
Face Mapping
External Monitoring: Track
Ground Monitoring Points
Remote access robotic scanned survey data 24 hrs /day
Plan of monitoring surface
Track Monitoring Points
In tunnel monitoring
In tunnel monitoring
Designers Expected Max Settlement = 6 to 8 mm
Daily “Permit To Tunnel” meeting room
Surface settlement: Actual vs Predicted
No alarm triggered during Construction
Outcome
A few other project
elements
44
45
• A 4D project – design, plan and build
around track possessions
Key challenges
46
Key challenges
• 4D project – design, plan and build
around track possessions
Multi-disciplinary
response
47
• Design co-ordination drawings
48
• Construction staging diagrams
Multi-disciplinary
response
49
• Methods Department – managing site
Multi-disciplinary
response
50
• Methods Department – managing site
Multi-disciplinary
response
Questions
51