Survey of New Tunneling Projects, Their Costs, Application, and Effect on Rail System Performance Brian J Larkin, P.E. Larkin & Associates ‐ San Francisco, CA
Survey of New Tunneling Projects, Their Costs,
Application, and Effect on Rail System Performance
Brian J Larkin, P.E.
Larkin & Associates ‐ San Francisco, CA
Background
• Exclusive Right of Way Operation• At Grade• Grade Separated
• Elevated• Underground / Below Grade
Larkin & Associates ‐ San Francisco, CA
Some Tunneling Techniques
• Cut & Cover• Sequential Excavation Method (SEM)• Tunnel Boring Machines
Larkin & Associates ‐ San Francisco, CA
Sequential Excavation Method
Larkin & Associates ‐ San Francisco, CA
• Advantages• Fewer Spoils to Dispose of• Good in Sandy Soils
• Disadvantages• Slow• May Require Extensive Soil Treatment
Tunnel Boring Machines
• Open Faced• Slurry Shield• Earth Pressure Balance (EPB)
Larkin & Associates ‐ San Francisco, CA
Open Faced Machines
• Only Support Themselves • Good for Use in Hard Rock• Danger of Collapse in Soft Ground
Larkin & Associates ‐ San Francisco, CA
Slurry Pressure Balanced
Larkin & Associates ‐ San Francisco, CA
• Slurry Pumped from the Surface• Mixes with Cuttings to Maintain Pressure• Used in Soft Ground with High Water Pressure
and Large Amounts of Ground Water.
Earth Pressure Balanced
Larkin & Associates ‐ San Francisco, CA
• Shielded Cutting Face• Screw Conveyor Removes Spoils• Machine Installs Liner Segments• Advances by Pushing off Liner• Can Advance 50 feet /day
BART Warm Springs Extension
• One mile of cut & cover tunneling• Contract cost - $137 million• $82 million for tunneling • $55 for excavation support to protect aquifer• Birds nests
Larkin & Associates ‐ San Francisco, CA
NYCTA 7th Avenue Subway (SAS)• 8.5 mile extension of No 7 line in Manhattan• Includes freezing ground ahead of TBM• Varying geology includes hills and valleys,
schist, sand and silt• $350 million tunneling Contract• Two tunnels – 15,000 linear feet
Larkin & Associates ‐ San Francisco, CA
East Side Access (ESA)
• Connects LIRR trains to Grand Central Station• Two – 22.5 foot diameter tunnels• Slurry shield machines• 10,500 feet of tunnel - $718 million in
Manhattan
Larkin & Associates ‐ San Francisco, CA
No. 7 Line Extension
• Extends existing line 1.7 miles from Times Square area to Penn Station
• $1.14 billion tunneling contract – two TBMs combined for 9,300 feet of tunneling
Larkin & Associates ‐ San Francisco, CA
SF MTA Central Subway
• Low bid for tunneling contract - $233,584,015• Two 1.7 mile bores• EPB machines
Larkin & Associates ‐ San Francisco, CA
LAMTC Gold Line Eastside Extension
• Includes twin tunnels – two underground stations
• Each tunnel is 7,000 ft.• EPB machines 21ft – 5 in cutting diameter• Cost of tunnels - $268 million
Larkin & Associates ‐ San Francisco, CA
Guadarrama Tunnel
• Tunnel on Madrid – Valladolid HSR line• Each tunnel is 17.65 miles• TBM diameter – 9.5 m (31 ft – 2 in)• Cost of tunnels - $17 billion • Production rate – 50’/day
Larkin & Associates ‐ San Francisco, CA
San Francisco Market Street Subway
• Subway service started in 1979• Total Market Street Ridership –98,000• Post 1979 Ridership – 136,000• Capital Cost - $380 million• Travel Time for 4.5 miles
• Surface – 25 minutes• Subway – 10 minutes
Larkin & Associates ‐ San Francisco, CA