Seymour-Capilano Twin Tunnels
Delivering clean drinking water to Vancouver residents
Metro Vancouver
|
Canada
|
2002-2015
7.1-km-long twin tunnels
bored under Mount Fromme and Grouse Mountain
3.8-m-diameter,
predominantly unlined tunnels in rock
Welded steel watermain pipe in tunnels under high hydrostatic pressure
2 raise-bore shafts 275 m deep and one drill and blast shaft 180 m deep.
Challenges
- Metro Vancouver required an efficient solution to the challenge of treating drinking water from two reservoirs separated by a mountain range.
- Tunnel design accommodated up to 650 metres of rock cover.
- Tunneling avoided disruptive open-cut pipelines in North Vancouver streets.
- Protecting the overlying groundwater table from the pressurized tunnel was critical to a successful design.
Solutions
- The twin tunnels link the Capilano Reservoir with the new, state-of-the-art Seymour-Capilano Filtration Plant, which has a 1.8 billion litres/day capacity.
- Tunnel depth, alignment, and shaft locations were chosen to minimize tunneling in fractured rock and avoid glacial soil-filled valleys.
- Tunnel depth required an optimized permanent rock-support design in the unlined sections of the tunnels.
- Steel liners designed for up to 300 metres of head pressure were installed where tunnel watermain pressures exceeded groundwater levels.
- Boring unlined tunnels in natural granite saved CAD$40 million and 10 kilometres of pipeline.
- Infrared technology provided quality assurance for grout backfill behind the steel tunnel liners. Computational fluid dynamics (CFD) aided the design of sand traps and ensured any loose material from the unlined tunnel will be intercepted.
Highlights
- Metro Vancouver’s first treated water tunnel to include unlined sections.
- Temporary caverns at shaft and tunnel junctions enabled tunnel-boring machine (TBM) operations and steel pipe installation.
- Innovative design approaches produced a resilient tunnel and employed new technology.
- Recipient of the 2016 Award of Merit, BC Association of Consulting Engineering Companies.
Hatch diseñó el túnel para este importante proyecto, que ahora transporta agua sin procesar desde el embalse de Capilano hasta la planta de filtración de última generación Seymour-Capilano en la reserva de conservación de Bajo Seymour. Hatch participó en este proyecto desde sus comienzos, a partir de los estudios iniciales para evaluar y definir los parámetros del proyecto. Durante el transcurso del proyecto, Hatch ha demostrado ser un consultor confiable y receptivo, capaz de planificar, supervisar y llevar a cabo la multitud de tareas implicadas en el diseño y construcción de dos túneles en roca profunda de 7,1km de longitud a través de la cadena montañosa de Columbia Británica.
El profesionalismo, la habilidad técnica y la colaboración que ha demostrado el equipo de Hatch nos han permitido trabajar juntos para entregar este proyecto importante y cumplir con nuestro objetivo de proveer agua potable segura y de alta calidad para las generaciones futuras.
Project Numbers
Capital cost of CAD$250 million14.2 km of 3.8-metre-diameter, main-beam TBM-driven tunnel
Shafts of 180m and 275m depths
Tunnel depths of up to 650 m.
Approximately 5.5 km of 3.0-metre-diameter pipe installed in tunnels and shafts