A unique application of Diaphragm Wall to facilitate the excavation of New River Channel on The Port Lands Flood Protection and Enabling Infrastructure Project in Toronto, Ontario-PowerPoint Presentation

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This presentation describes a unique use of diaphragm wall construction for Toronto’s Port Lands Flood Protection and Enabling Infrastructure Project. Diaphragm walls are reinforced concrete walls excavated under slurry, capable of deep excavation, complex layouts, and installation close to existing structures. They also provide rigid earth retention and can serve as load-bearing elements.<br /><br />At the Port Lands site, the ground conditions were difficult: hydraulic fill, sand and silt with organic layers, contaminated soils, cohesive clays, and bedrock at significant depth. The project used diaphragm walls in three main areas: the West Plug Wall, North Wall, and South Wall. These walls served both temporary and permanent functions, including excavation support, hydraulic cut-off, and structural elements for later construction.<br /><br />The West Plug Wall was especially innovative. It operated first as a dock wall for dredging, then as a dam to keep Lake Ontario out during river excavation, and later as a load-bearing wall supporting bridge offloading. After the river channel was completed, the wall was demolished.<br /><br />Compared with the original secant pile design, the diaphragm wall offered major benefits: less horizontal movement, better verticality control, fewer construction joints, a shorter schedule, and about 25% lower cost. Hydro-mill joints were used to improve water tightness by overlapping panels and creating grooved joint profiles.<br /><br />Wall movement was monitored in real time using in-place inclinometers linked to cloud-based reporting. Performance was strong: during service from 2020 to 2024, wall deflection remained around 10 to 15 mm, the structure survived extreme temperature changes, and water ingress was limited. The West Plug Wall was fully decommissioned in fall 2024.

Keywords

diaphragm wall

Toronto Port Lands

flood protection

reinforced concrete

slurry excavation

hydraulic cut-off

West Plug Wall

hydro-mill joints

wall deflection monitoring

load-bearing structure