100,000 cyds excavation, strand tieback anchors and shotcrete shoring.
This project required careful anchor installation through soft peats and silts to prevent soil hydrofracturing, likely to happen if conventional high pressure air rotary methods common in Vancouver were used. Hydrofracturing would create voids and subsequently, short and long term settlement.
Southwest Contracting redesigned the anchor installation to allow for continuous casing installation to seal into the underlying tills without using air. Once the casing was sealed into the till, the cuttings were removed from the inside of the casing using conventional air track drilling. The large loads required redesign of the anchor bar to a strand tendon to fit into the smaller anchor hole. Ultimate bond stress tests using the smaller hole size were performed prior to redesign.