A tunnel-boring machine similar to the one that was used on the
Northwest Side Deep Tunnel Project.
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weight: 800 tons (1,600,000 lbs)
length: 430 ft
motors: eight 350 hp electric motors
energy req'd: 5,000,000 watts (at max. output)
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Previous Jobs Used On:
1977 - Chicago, Illinois - Weller Creek Sewer Tunnel - 4.1 miles,
1985 - British Columbia, Canada - rail tunnel - 5.3 miles
1993 - Dallas, Texas - transit tunnel - 7.5 miles
2000 - Chicago, Illinois - tunnel at Fermi Lab - 0.5 miles
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Cutter Head:
By rotating the cutter head against bedrock, small chips of rock are excavated using pressure and a series of disc cutters (seen on the front face of the cutter head)
- 22 feet in diameter
- 60,000 pounds maximum thrust capacity
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Propel & Grip System:
This section of the machine performs two critical functions. When boring is taking place, massive, hydraulically controlled arms on the side prevent the machine from sliding backwards by pushing against the tunnel walls to hold the machine in place. At the same time, another hydraulic system pushes the cutter head forward.
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Conveyor System:
Sometimes called the trailing gear, this section of the machine contains a 36-inch-wide conveyor belt system that transports rock fragments to the tail end where the excavated material is loaded into rail cars. |
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