A section of Clarke Road is closed after another sinkhole formed along the bored tunnel route for the new SkyTrain Evergreen Line.
The small hole appeared Friday evening near where the street intersects with Seaview Drive and prompted a road closure in the area. According to the Evergreen Line Project Office, the tunnel boring machine stopped in the area to allow regular maintenance to inspect and replace the cutterhead tools.
“While completing maintenance under Clarke Road at Seaview Drive, despite our ground improvement program, some additional ground material entered the TBM chamber and an air pocket developed,” reads a notice by the project office.
“The air pocket resulted in a hole in the asphalt on Clarke Road. Safety is the first priority on the Evergreen Line Project and crews are addressing the situation within a secure fenced area.”
— BC Transportation (@TranBC) June 6, 2015
The road was repaired by Saturday morning, but the area is still closed to traffic as a precaution.
Tunnel construction is considerably slower than anticipated due to poor soil conditions as the tunnel runs through loose glacial till deposits.
Construction for the $1.4 billion project, an 11 kilometre and six station addition to the region’s SkyTrain system, is largely on schedule. However, ongoing complications with tunnelling have delayed the extension’s opening date from summer 2016 to fall 2016.
Tunnel boring began in March 2014 and was originally anticipated to take 200 days to complete – a rate of about 10 metres of new tunnel length per day.
The provincial government is overseeing the Evergreen Line project, which is being built by SNC-Lavalin and its partners.