Hells Gate, Fraser Canyon, BC

Engineering tunnels are driven by drill and blast, road header and TBM methods. An issue for all these types of tunnels is support requirements for long term, safe operations. The support requirements will depend on the rock conditions, stress levels, tunnel span and type of usage, and the types of support may range from spot bolting to a full concrete lining. Another issue that may need to be addressed is repair of existing tunnels.

Lake taps - a particular skill is the design and implementation of lake taps to connect natural reservoirs to water supply and pressure tunnels.


  • Tunnel site investigations including engineers engineering location studies, geological mapping, diamond drill core logging, with and without core orientation, and ground water studies;
  • Laboratory testing of rock strength;
  • Support design including rock bolts, shotcrete, steel sets and concrete linings;
  • Preparation of excavation sequences and temporary support measures in multi-heading drives.

Wyllie & Norrish Rock Engineers Ltd. | Canada

1400–750 West Pender St, Vancouver, BC V6C 2T8

(604) 418-4617 | dwyllie@wnrockeng.com

Wyllie & Norrish Rock Engineers Inc. | United States

704-228th Ave NE, #773, Sammamish, WA 98074

(206) 790-3476 | nnorrish@wnrockeng.com