McNally-PCL-Foundation jv construction 6.4 km of twin tunnel with five stations to connect Yonge Subway with Don Mills Road. Two Lovat 5.9 m-diameter EPBs exceeded scheduled advance rates of 15 m/day/face in glacial deposits with boulders. 3.3 km west drives completed towards end-1998 and TBMs removed for minor refurbishment prior to starting east drives for completion end-1999. 5.2 m i.d. precast concrete lining in 1.4 m rings with 7 bolted gasketted segments including key, waterproof to 4 bar. Rings with left and right tapers are provided in equal numbers to facilitate both horizontal and vertical curves. March 1999.
