Elgin Mills PD7 Watermain Ontario

Challenges

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.