Owner
Metrolinx and Infrastructure Ontario
Client
Mobilinx [WeBuild, Amico, Hitachi, Transdev, John Laing]
Cost
$4.6 billion CAD
Timeframe
November 2022
— May 2023
Services performed
Design of ground improvement campaign to allow controlled excavation utilising shotcrete for a box jacking under three live GO train tracks.
Description
The Hurontario LRT line is 18 km of new rapid transit between Port Credit and Steeles in Brampton. It crosses under the GO trains near Port Credit Station using a box jacking system. Dr. G. Sauer & Partners designed a ground improvement campaign using a mix of vertical (from surface) and horizontal (from within excavation) tube-à-manchette grouting to stabilise the ground. In addition a controlled and staged excavation sequence was designed utilising shotcrete, face subdivision and grout lances as additional tool box items. A Senior Tunnel Engineer on site provided engineering support and advisory services during excavation for the staged excavation ahead of each box jacking step utilising a RES-meeting process.
Geology
Mixed face conditions consisting of hard till, clay and shale as natural ground and two layers of uncompacted loose gravel backfill materials from an adjacent bridge abutment construction. Obstructions such as wing wall footings.
Location
Port Credit, Mississauga, GTA, Ontario, Canada
Highlights
- Horizontal and vertical ground improvement design.
- Using grout mix design to create cementitious matrix connecting gravel stones.
- Controlled excavation process utilising SEM-like toolbox items and RES process on site.
3D Imaging of quantitative grout take for tube-a-manchette horizontal grouting and temporary mini-piles to support tracks above
Final stages of excavation and ground improvement from within box with temporary rail support above