Trans Mountain Expansion Pipeline (TMEP)

LOCATION: Edmonton, Alberta to BC Lower Mainland

BGC has been involved in detailed engineering support for the Trans Mountain Expansion Project (TMEP) since 2011. In the beginning, BGC assisted the Trans Mountain team with terrain mapping and field verification of their 1100 km (680 mi) of pipeline. The ground conditions ranged from competent bedrock to extremely low strength marine clays. BGC’s support included route-wide geohazard assessments including landslides, rockfall and debris flow potential; provision of a route-wide quantitative geohazard failure frequency assessment; ARD/ML route assessment; and shallow water characterization for buoyancy control. In addition, BGC performed detailed assessments of liquefaction and seismically induced ground displacement along the route at sites screened as the highest hazard, incorporating subsurface information from more than 70 SPT drill hole and cone penetration tests along with hundred of terrain mapped polygons. BGC completed pipe-soil structural analyses to characterize the interaction of the pipeline with permanent ground displacements from liquefaction or seismic-induced slope failures.

BGC continued to support Trans Mountain through the detailed design phase by completing hydrotechnical hazard characterization for over 800 trenched water crossings, detailed geotechnical investigations for 50 major trenchless crossings, investigations at over 200 road and rail bore crossings, and a feasibility investigation of a 4 km (2.5 mi) tunnel. All designs considered changing conditions due to climate change with the overall project following a risk-based design.

In 2019, BGC’s role transitioned into a construction support role. BGC acts as the Geotechnical Engineers of Record for our designs and as Owner’s Engineer providing oversite on geotechnical and hydrotechnical challenges encountered during construction. Over the 1100 km of construction, BGC has had a team providing continual field presence across the project including at rivers for hydrotechnical site support, at road and rail crossings for support for monitoring for unplanned settlement, and at steep slopes or within high-risk geohazard areas with on-site geotechnical observations and mitigation support for unforeseen conditions or where rapid field-based adjustments and decisions are required.

As the construction reaches completion in 2023, BGC’s role will transition again to proactively managing TMEP’s geohazard management program in Cambio™.