Design and Construction Considerations for Atwater Water Intake and Conveyance Tunnel in Montreal

摘要

The City of Montreal plans to secure the existing water intake of the Atwater Treatment Plant by permanently isolating the section of the channel adjacent to nearby highway that is at risk from contamination and spills and constructing a new intake upstream. The new intake will be linked to the existing intake by a 877 m (0.5 mile) long 6 m (20 ft) diameter 30 m (100 ft) deep tunnel, two 6 m (20 ft) diameter vertical shafts, and an cut and cover connecting structure to the existing valve chamber. The geology consists of shale that is known to be fissile and slaking and is being excavated by drill-and-blast. The paper provides design considerations of this siphon tunnel as well as construction updates.