Client: The Regional Municipality of York, Ontario, Canada
Location: Ontario, Canada
Project Value: $6.20m
Description: Specialist Shaft Construction & Microtunnelling Contract
The Elgin Mills watermain project was part of York Region’s Long Term Water Supply Master Plan, and the Water and Wastewater Master Plan 2009.
The prime objective of the PD7 600mm ID CPP watermain was to reinforce the current watermain systems serving the towns of Richmond Hill and Markham. Considering the location, with a high density of residential and commercial buildings and in order to mitigate local traffic disruption, the Contract specified that the watermain be constructed utilising trenchless methods.
Ward & Burke were responsible for the construction of a microtunnel and the installation of the 600mm CPP watermain.
Once the tunnel was completed, the 600mm ID CPP feedermain was installed using a Ward and Burke engineered technique known as “pipe flotation” in conjunction with shaft-based pipe installation frame. A specifically designed cellular grouting campaign, was then employed to grout the tunnel/ watermain annulus.
The designed and constructed tunnel alignment for the Elgin Mills PD7 watermain, resulted in the longest, curved microtunnel ever constructed in North America/Canada, and is a testament to the Engineering and Operational Skills of Ward & Burke.
The project site geology was primarily composed of stiff cohesive glacial tills, and saturated silts/sands. Acknowledging these challenging soil conditions, Ward & Burke proposed to construct the 740m long, 1500mm ID microtunnel using a Herrenknecht AVN1500 microtunnel boring machine (MTBM), from one specifically designed microtunnel drive shaft.
The long-distance microtunnel was constructed in one-pass and the primary tunnel liner, consisted of a 1500mm ID precast microtunnel pipe.
The resulting designed alignment consisted of three engineered horizontal curves with straight tangents in between each curves. In order to execute the curves, a state of the art, high precision VMT tunnel guidance system was installed in the MTBM. This system provided the MTBM operator will real-time information, with regard to the MTBM orientation.