On the job with tunnel boring machines Rexy and Renny

renny tunnel boring machine

Ontario Construction News staff writer

While Rexy and Renny slowly tunnel their way east, construction is also starting at the extraction shaft near Scarlett Road and Eglinton Avenue West later this spring, with headwall construction at Martin Grove Road and Kipling Avenue also starting this spring.

As tunnel boring machines dig through the earth, soil and rocks are removed by a conveyor belt and transported back to the launch shaft site. This material is then hauled off site for proper disposal.

The machines install tunnel liners made of reinforced concrete and designed to support the earth and resist pressure from soil, rocks, and water that surround the tunnel to give the tunnels their structure – critical for safety and keeping the TBMs moving.

As a TBM moves forward, it installs the precast tunnel liners using a special built-in device. The TBMs advance through the earth by pushing off the recently installed rings of tunnel liners using hydraulic jacks.

The precast tunnel liners for the Eglinton Crosstown West Extension are being manufactured by CSI Forterra Canada in Whitby – the same company that is supplying liners for the Scarborough Subway Extension.

The Eglinton Crosstown West Extension project will require 7,400 concrete rings for its twin tunnels.

Some facts about Renny and Rexie:

They each weigh about 750 tonnes each, about five times the weight of a blue whale.

They are each 6.58 metres in diameter, which is taller than a giraffe.

At 131 metres in length, they are each a little over a quarter of the height of the CN Tower.

To get the site ready to start tunnelling, a launch shaft was made that could hold the volume of 11 Olympic-size swimming pools.


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