ABSTRACT
Tunneling under rivers was considered impossible until the protective shield was developed in England by Marc Brunel. Brunel’s shield, rectangular in plan, was successfully employed in driving the world’s first underwater tunnel, the Thames Tunnel, under the River Thames at London from 1825 to 1842. Throughout the time several shields were developed, and the combination of shield and compressed air made tunneling possible under the largest rivers. In Canada, St. Clair tunnels were the first subaqueous tunnels, initially completed in 1891 and replaced by a new larger tunnel in 1995. This paper intends to provide a discussion of challenges and solutions for subaqueous tunnels built in Canada including St. Clair, Detroit-Sarnia, Ashbridge Bay Treatment Plant Outfall, Port Mann Water Supply Tunnel, Second Narrows, Annacis Wastewater Treatment Plant Outfall, Mid-Halton Outfall and the Annacis Water Supply Tunnel projects.
