Kenilworth LRT Tunnel Construction

The METRO Green Line Extension will run in a tunnel northeast of West Lake Street, pass underneath Cedar Lake Parkway, and return at-grade approximately 400 feet south of the Cedar Lake Channel (Kenilworth Channel).

Duration and location

Tunnel sheet piling work will start near Park Siding Park and move north toward Cedar Lake Parkway. With the sheeting installed, the excavation work and tunnel structure construction activities will then take place. Tunnel excavation began in 2020.

What to expect

Expect the following activities throughout tunnel construction:

• Operation of heavy machinery, including engine noise and back-up alarms
• Sawing of metal and concrete
• Frequent trucks moving through the corridor hauling materials such as soil and concrete
• Noise associated with moving sheet piles, bracing, and other construction materials in the work area
• In the winter, lighting rigs will be on site to allow crews to work after sunset until the end of approved working hours
• Other common construction activities

If you have any concerns or questions about LRT tunnel construction, please call the 24-hour Construction Hotline at 612-373-3933. Issues big and small routed through the hotline will be addressed in a timely manner.

Construction activities

LRT tunnel construction includes multiple phases of activities: sheet pile installation, soil excavation, and tunnel structure construction. Some of this work will occur simultaneously. Tunnel construction activities will progress through a “cell‐by‐cell” construction approach.

• Phase 1: Sheet Pile Installation
  Install approximately 1,300 pair of sheet piles to create 100-foot-long rectangular shaped cells which will contain groundwater. A hydraulic press-in-piler will be used to minimize noise and vibration during sheet pile installation.
• Phase 2: Excavation and Bracing
  Excavate soil for the tunnel using equipment such as excavators and clamshell excavators. Expect a steady flow of trucks in the area to move soil off the construction site. Bracing will be installed between the sheet pile walls as the excavation extends to the bottom of the tunnel.
• Phase 3: Concrete Seal Installation and Water Removal
  Place concrete into the excavation with a pump truck to create a seal on the bottom of the tunnel. After the concrete has cured, the cell will be watertight. Pumps will then move water from the cell under construction.
• Phase 4: Bottom Formwork & Waterproofing
  Install formwork for the base of the tunnel, place concrete using pump trucks and install waterproofing over the concrete after it has cured.
• Phase 5: Walls & Top Formwork
  Install formwork for the tunnel walls, place concrete using pump trucks and install waterproofing over the cured concrete. Similar activities will be repeated to construct the top slab. Once the top slab is complete the contractor will backfill over the tunnel and will construct the bike trail and landscaping.

Next steps

Once the LRT tunnel construction is complete, crews will:

• Install the tracks, communication, and electrical systems
• Backfill over the tunnel
• Reconstruct the final trail
• Restore the landscape