FORT ST. JOHN, B.C. – B.C. Hydro has started the tunnel lining process this week on the first of two Site C diversion tunnels.
According to B.C. Hydro Community Relations Manager, David Conway, this part of the work is the last step in the construction of the diversion tunnels prior to river diversion in the Fall of 2020.
Conway says the tunnel lining process involves using a slip form where concrete is pumped through small openings located around the slip form, enabling it to cure in a perfect circle outside of the form.
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Each slip form weighs 400 tonnes and is 12 metres long.
The tunnels themselves are 10.8 metres in diameter.
Each pour will take two to three days to cure and the liner thickness can range between 40 cm and 200 cm.
In total, about 41,000 cubic metres of concrete will reinforce the walls of both tunnels.
The lining of both tunnels is expected to be complete by early 2020.