Hydro One Midtown Tunnel Project

Project Highlights

Role: General Contractor

Project Delivery: Bid-Build

Tunnel Equipment: 3.9 EPB TBM

Primary Support: Ribs & Lagging/ Cast in Place Concrete

Ground Conditions: Shale Bedrock

Project Description

The Hydro One Midtown Tunnel Project involved the construction of a 2.4 kilometer utility tunnel from Bayview Avenue to Yonge Street. The project was to support the City of Toronto increasing population and provide enough electricity to power 25,000 homes. Construction of the project required three shafts at depths between 55m to 74m and a 3.9m utility tunnel in shale bedrock 60m below ground. The 3m, 2.4 kilometers long tunnel was excavated using a 3.9m diameter TBM designed, built, maintained and operated by Technicore Underground.

Owner: Hydro One Networks Inc.

Start Date: April 2012

Completion Date: October 2014

Drive Length: 2350 meters

Diameter: 3.9 meters

Consultants: MMM Group Limited

Contract Amount: $38,200,000

Ground Conditions

The tunnel was 2.4km in total length and comprised of very competent shale for the whole length except the final 100m.  This final stretch was a major fault and crush zone which required a horseshoe rib and lagging support for the excavation.