Port Mann Main Water Supply Tunnel – Ground Freezing the TBM face under the Fraser River

Case Studies / 8 October 2020 by Joseph A. Sopko, Ph.D., P.E. Moretrench Behzad Khorshidi, Ph.D., P.Eng. McNally Construction Inc. Brian McInnes, EIT McNally Construction Inc. / Keller

Credit : Keller - Distribution Manifold

The Port Mann Main Water Supply Tunnel involves a 1km long tunnel beneath the Fraser River from Surrey to Coquitlam, BC. At depths of up to 60m below ground, the earth pressure reached 6 bar. The tunnel is constructed using an EPB TBM and gasketed precast concrete segmental liner. The tunnel and two shafts were constructed in a variety of soil conditions ranging from soft to stiff clays and silts, to compact to very dense sands and gravels.