Stage 1 in Ottawa’s planned light rail network consists of a new 12.6‑kilometer (7.8 mi) electrified light rail transit line between Tunney’s Pasture and Blair Stations. The project includes 2.5 kilometers (1.6 mi) of mined tunnels with three underground stations. The project also includes approximately 152 meters (500 ft) of cut-and-cover tunnels at each end of the mined running tunnels.
The Stage 2 extension consists of 13 kilometers (8 mi) of new rail and 10 new stations for the east – west Confederation Line. Approximately 3.2 kilometers (2 mi) consist of cut-and-cover tunnels with two new underground stations and a connection to one existing underground station.
Delve Underground is a joint venture (JV) member of Capital Transit Partners, providing program management services and engineering and construction support for Stages 1 and 2 of the Ottawa Light Rail Transit project.
We were responsible for preliminary engineering and preparation of technical elements of the procurement documents for the tunnels and underground stations. This included development of concept design drawings, calculations, technical reports, and Project Specific Output Specifications (PSOS). Delve Underground worked closely with its JV partners for the development of the PSOS and provided technical input for the Project Agreement. We also provided construction support during the final design and construction phases for Stage 1 and Stage 2.
In Stage 1, the mined station located below Rideau Street was partially excavated through a buried glacial valley below the groundwater table, and the two downtown stations were excavated in close proximity to existing adjacent structures with deep basements.
Portions of the Stage 2 cut-and-cover tunnels and station excavations required watertight excavation support systems to prevent consolidation settlements from occurring as a result of groundwater drawdown.