Caisson and Soldier Pile Excavation Support Design for Rail Underpass Construction

Location: Central Avenue & Adelaide St. North – London, ON

The Adelaide Street North Grade Separation project in London, Ontario, involves constructing an underpass beneath active Canadian Pacific Railway tracks to alleviate traffic delays caused by train crossings on Adelaide Street North. Located 500 meters south of Oxford Street, this major infrastructure job required excavation support design to ensure safe construction adjacent to active railway tracks.

InGeo Design partnered with Bauer Foundations Canada to deliver specialized GeoStructural design services, developing a combined caisson and soldier pile lagging support system. The system incorporated two levels of struts and tiebacks and included design of a temporary bridge bearing on the caisson walls to support the tracks during construction.

Key Challenges

• Designing excavation support adjacent to active CN train tracks.
• Incorporating a temporary bridge bearing system to maintain rail stability during construction.
• Maintaining a cut off system throughout the construction sequence.

InGeo’s Role & Scope

• Engineering design of a combined caisson and soldier pile lagging excavation support system.
• Design of two-level struts and tiebacks to resist excavation loads and protect rail infrastructure.
• Design of an 11m diameter, 13.5m deep shaft primarily with caisson walls.
• Design of a permanent caisson soil support wall adjacent to future pedestrian sidewalk.
• Ongoing site inspections to verify adherence to design parameters.