Shotcrete shoring work was done as part of an 8.1km extension of Calgary's existing Light Rapid Transit system. As part of the extension, there were 2.3km of trench that required temporary shoring to allow for the construction of permanent tunnel and trench structures, and 0.7km of permanent shoring for an open trench.
Shoring for the Calgary West LRT project involved numerous challenges, all of which were met by Southwest:
- Work on the project was to be completed in just 18 months.
- Shoring during the winter with temperatures as low as –30°C was accomplished by heating and hording the shotcrete.
- Shoring with shotcrete and anchors is not typically done in Calgary; typical shoring in Calgary is done with soldier piles and lagging or sheet piling due to gravels.
Scope of Work
- Temporary soil nail shotcrete shoring: ~ 250,000 ft² of shotcrete with 24.34 miles IBO and 19.32 miles of conventional soil nails.
- Permanent soil nail shotcrete shoring: ~ 94,200 ft² of shotcrete and 27.56 miles of soil nails.
- Ground conditions: Temporary shoring consisted of clay overlaying gravels/boulders, which, in turn, were overlaying mudstone/sandstone. The ground conditions for the permanent work consisted of gravels/boulders overlaying mudstone/sandstone.