LRT Tunnel Extension Project
Light Rapid Transit (LRT) North tunnel Extension Project
The LRT system in Edmonton, Alberta is a rapid transportation development powered by electricity and carries over 92,000 passengers on an average day.
In May 2010, the City of Edmonton’s transportation department announced its recommendation for an extension of the north line. The construction management team was selected to North Link Partnership in March 2011. The North Link Partnership is comprised of SNC-Lavalin Group Inc. and Graham Infrastructure Ltd.
Flatiron Construction was awarded the contract to tunnel two concurrent 440-metre extensions (880 meters total) branching off the existing LRT line at Churchill Station, and running on surface from MacEwan University to the Northern Alberta Institute of Technology. This extension will link major postsecondary and health care centers to the LRT system.
Flatiron contracted Multicrete™ to provide materials, equipment, knowledge and skill to shotcrete the exposed tunnel wall for stability.
Multicrete’s materials were produced in accordance with the project’s stringent mix design criteria. 2.138 metric ton (1 cubic meter) bags of pre-mixed shotcrete were used. To date, 2350 cubic meters of shotcrete has been supplied. Additionally, top of the line equipment was supplied or fabricated for shotcreting: Huron 4 Transmixer and Kubota 520. Both units are complete with Aliva 257 shotcrete pumps, Aliva 302 robotic application arms, and liquid accelerator dosing systems.
The process for building the tunnel consists of:
• Excavating one meter
• Spraying 2 inches of Multicrete’s shotcrete safety coat for support using the Huron 4 Transmixer
• Erecting metal trusses
• Spraying 4-6 inches of shotcrete for one more meter
The project is attempting to maintain an advancement of 4 meters per day.
As Multicrete™ has extensive experience shotcreting underground mining tunnels, their technical expertise in mix design modifications and additives, such as accelerator, was also provided.
*Photo: Edmonton Journal