Tunnelling works are well underway on Metrolinx’s 5.3 billion-dollar Eglinton Crosstown Light Rail Transit (LRT) Project. Dr. G. Sauer & Partners Corporation (DSP) are proud to be a part of the Crosslinx Transit Solutions (CTS) Group, focused on delivering a successful tunnelling project in the city of Toronto. Our on-site team are providing site supervision and design support services to the CTS Construction (CTSC) team on three of the future stations located along Eglinton Avenue and in the areas of Laird Drive, Avenue Road and Oakwood Avenue respectively.
Sequential excavation method (SEM) Tunnel construction at Laird and Avenue stations are in progress. Work on Laird Station commenced in the summer of 2017 with the construction of the 14m diameter Access Adit. Currently works are progressing with the construction of the larger 17m diameter Cross Cut Cavern in the Main Shaft and construction is due to begin on the 18m diameter Platform Caverns in January 2018.
At Avenue Station, DSP are currently supervising the SEM works of the Access Adit, completion of the Adit is expected in spring 2018. Prior to starting tunnel excavation, a pre-support pipe roof canopy some 12-15m long is carefully installed to support the ground immediately above the Adits and Caverns and to mitigate ground movement. A top heading excavation with combined bench/invert plus temporary invert sequence has been utilised in the upper sections to construct the side-drifts with additional pipe roof support measures prescribed throughout the tunnel construction.
Daily reviews of tunnel monitoring instruments are performed by our team of monitoring specialists, as well as round the clock tunnel inspections and supervision by our professional team of engineers and inspectors, to ensure the highest levels of quality are achieved.
The ground in the area of SEM activity, at all three proposed stations, adds to the complexity of the project and comprises of plastic and non-plastic till as well as alternating interstadial sand to gravel layers and plastic glacio-lacustrine soil deposits. In all of the above locations, water control and mitigation measures are undertaken by CTSC to manage the ground during construction and provide a safe environment for tunnelling crews to operate in.
In order to optimise cost and schedule without jeopardising safety and quality, DSP are providing design support to CTSC upon request. Our team of engineers are liaising closely with CTSC to deliver a project of the highest safety and quality and to meet the requirements of the CTS Group.