The sinkhole, eight meters (26 feet) wide and 12 meters (39 feet) deep, formed on Waller Street at the site of an entrance, under construction, to the city's light rail tunnel near the University of Ottawa, city officials said. The cause of the sinkhole was not known but no one was injured.
A statement from city government said crews from tunnel builder Rideau Transit Group had started 24-hour tunneling operations Wednesday, and were at work when the sinkhole formed.
Work was underway to fill the sinkhole and stabilize it. Water and other services to nearby buildings have been cut off. Traffic and buses are also being rerouted around the affected area, the Canadian Broadcasting Corp., reported Friday.