Light load: Tunneling transport

by MM&D staff

COQUITLAM, British Columbia—A piece of equipment designed to move a total of two kilometres has begun a journey of more than 4,000km.

A tunnel boring machine designed and built by Caterpillar Tunneling Canada Corp in Toronto is being shipped to Coquitlam, British Columbia, where it will be used to dig a tunnel that will run west of Barnet Highway in Port Moody to south of Kemsley Avenue in Coquitlam.

The 2.2km tunnel is part of the province’s $1.4 billion Evergreen Line Advanced Light Rapid Transit (ALRT) project. The Evergreen Line will link Burnaby, Port Moody and Coquitlam and be fully integrated into the existing system, connecting with the Millennium Line at Lougheed Town Centre Station. It is expected to carry 70,000 passengers and remove 40,000 cars off the road everyday by 2021.

Because of the immense size of the machine—once completed, it will measure 85m long and 10m in diametre—it is being shipped in piece and will be assembled at the site. Assembly will take a couple of months, with tunnel construction expected to start in February 2014.

The first piece to make its way to BC is the cutter head, which weights 130 tonnes. The function of the cutter head rotates is to break up the ground while a conveyor system moves the spoils to the back of the machine for disposal. The machine also inserts the concrete tunnel ring sections as it moves, reinforcing the structure.

It is expected to take approximately one year for the boring machine to complete work on the tunnel. The machine will dig through through the ground at an average rate of eight metres per day.