Where the Tunnel Boring Machine goes, GKM Consultants and ShapeArray follow. Reusability allows the contractor to move ShapeArray along 4 km tunnel drive.
When the City of Montreal started work on a $64 million project to add 4.1 km of aqueduct pipe to help modernize the city’s municipal water system in 2015, they selected GKM Consultants and ShapeArray to monitor the work of a 2.3 m diameter tunnel boring machine (TBM).
The project's contractors followed strict conditions because the TBM's planned 4.1 km path ran near densely populated residential areas, numerous commercial structures, and important municipal infrastructure, including a highway overpass.
GKM Consultants deployed a comprehensive geotechnical monitoring strategy that included multipoint borehole extensometers, noise and vibration monitoring, and Measurand ShapeArray. This strategy allowed engineers to use the tunnel construction technique rather than trench excavation for the project, which ensured one lane of traffic in each direction on Jarry Street remained open throughout the work and the impact to the public was limited.
To monitor ground subsidence and lateral displacement, GKM Consultants installed 18 ShapeArrays in boreholes of either side of the TBM's path. As the TBM advanced, GKM took advantage of ShapeArrays re-usability, moving 10 of the 18 installations to other locations further down the TBM's path. GKM Consultants’ thorough monitoring strategy allowed continuous, real-time monitoring of the TBM’s movement and successful completion of the project.
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