Michels Canada is honoured to use trenchless construction techniques to complete two critical phases of the Tunneling Association of Canada’s 2020 Innovation Initiative of the Year.
Working as a subcontractor to Harbour Resource Partners on the McLoughlin Point Wastewater Treatment Plant (WWTP) in Victoria, BC, Michels Canada used Horizontal Directional Drilling to build a cross-harbour force main and Microtunneling to build an outfall for the WWTP.
Each phase of the design-build project posed unique challenges.
HDD
This 940-metre installation of a 1-inch thick, 42-inch diameter steel pipe spanned under Victoria Harbour from the James Bay area to Esquimalt. The final alignment was just under 260 feet below sea level, including 50 feet of ocean, 50 feet of sediment and 164 feet of bedrock. The drilling was completed through hard rock formation, requiring mud motors and hard rock tooling and ended at an elevation 15 feet above sea level on McLoughlin Point.
Microtunnel
A Herrenknecht AVN 1800 microtunnel boring machine (MTBM) was used to complete a 122-metre single drive of an 83.5-inch lined and coated Permalok steel pipe through granitic rock without tool changes. The MTBM was launched from a rock wall shaft below sea level inside the under-construction WWTP and exited into a rock trench 36 feet under ocean depth. After the drive and bulkhead was installed, an ocean retrieval was conducted to remove the MTBM from the tunnel.
Thank you to AECOM and Graham Construction, Harbour Resource Partners, for trusting us to turn these industry-stretching designs into reality.
