Billy Bishop Toronto City Airport Pedestrian Tunnel
Technicore Underground Inc.
This project for the Toronto Port Authority (TPA) involves 186 linear meters of tunnel, 10 m maximum tunnel diameter, 10 m minimum rock cover and two shafts (mainland and island sides). The tunnel is being constructed in shale rock (Georgian Bay Formation).
The pre-support system for the main tunnel excavation consists of a series of seven 1.8-m diameter horizontal interlocking secant bores (each 186 m in length) using two purpose-built rock TBMs, with each being excavated and backﬁlled with concrete in a sequential manner. This portion of the work started in December 2012, and was completed in May 2013. This will be followed by conventional rock excavation using a Liebherr 934 excavator with rock breaker attachment and a DOSCO roadheader.
The project reached a key milestone on Friday, Aug. 23, with a ceremony and barbecue at the island shaft to commemorate the breakthrough of the 186-m long main tunnel excavation under the Toronto Harbor Western Channel. Representatives of the owner, general contractor, tunnel contractor, private partner, design engineer and the local Toronto press were on hand for the event. Shale rock excavation of the central cut underneath the secant bore arch pre-support took approximately two months, with an average advance rate of approximately 5 m per day (two shifts per day, five days a week). The central cut excavation will be followed by sidewall excavation, rockbolting and shotcreting, invert excavation, waterproofing, and permanent lining installation.
Tunnel works, valued at $82 million, are expected to be complete by December with overall project completion in summer 2014.
Key parties involved in the project include Forum Infrastructure Partners (private partner); PCL Constructors (general contractor), Arup (tunnel design). In addition to serving as the tunnel contractor, Technicore built the TBMs.
Key Project Personnel: Technicore: Tony DiMillo, Gary Benner, David Marsland, Mike MacFarlane, Joe DiMillo. Design Project Manager: Jon Hurt (Arup); Tunnel Lead: Seth Pollak (Arup); Site Engineer: Andrew Cushing (Arup). Information: firstname.lastname@example.org.