Kenilworth LRT Tunnel Construction
Southwest LRT will run in a tunnel northeast of West Lake Street, pass underneath Cedar Lake Parkway, and return at-grade approximately 400 ft south of the Cedar Lake Channel (Kenilworth Channel).
Duration and location
Tunnel sheet piling work will start near Park Siding Park and move north towards Cedar Lake Parkway through December 2019. Sheeting installation throughout the corridor will continue through the winter, weather permitting, and into summer of 2020. With the sheeting installed, the excavation work and tunnel structure construction activities will then take place. Tunnel excavation is anticipated to begin in 2020. The most visible civil construction work on the nearly half mile tunnel will take two years.
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.
Phase 1: Sheet Pile Installation
Phase 2: Excavation and Bracing
Phase 3: Concrete Seal Installation and Water Removal
Phase 4: Bottom Formwork & Waterproofing
Phase 5: Walls & Top Formwork
What to expect
Expect the following activities throughout tunnel construction:
- Operation of heavy machinery, including engine noise, 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.
Once the LRT tunnel construction is complete, crews will install the tracks, communication and electrical systems; backfill over the tunnel, reconstruct the final trail, and restore the landscape.
View of the south portal area looking southwest, where the Kenilworth Trail meets the South Cedar Lake Trail. The tunnel portal areas will be fenced, and new seating areas will be established.
Rendering of the tunnel area post construction, with 25 years of tree growth. The configuration of trail and freight rail will be similar to today, with the LRT running underneath the Kenilworth trail.
Rendering of the north tunnel viewing area, looking north. Over the tunnel there will primarily be grass and the regional trail.