King Road Grade Separation Accelerated Underpass Construction by Jacking

Abstract

The project team designed an innovative strategy for the King Road Grade Separation which involved constructing a reinforced concrete tunnel structure ‘off-line’ of a major rail corridor, and subsequently sliding the completed four-track tunnel into place using an open-cut tunnel-jacking methodology. The slide utilized a one of a kind low friction, sliding base assembly. The structure was pushed into place under a fraction of the structure’s weight using a system of hydraulic jacks. This methodology allowed for a significantly abbreviated shutdown of mainline tracks over a single 72 hour period, minimizing operational impact to CN, Metrolinx and VIA trains.