BAUER Foundations Canada Inc. was contracted in 2019 by Norland Limited to construct a temporary secant pile wall for the Lot P residential high rise project in Vancouver, British Columbia.
BAUER utilized two BAUER BG28 rotary drill rigs to install the 196 x 880mm diameter filler piles and 98 x 880mm diameter structural piles up to an average depth of 13.6m. The pile lengths ranged from 9.6m to 15.7m and were em-bedded to a minimum of 2m into bedrock. The area beneath the toe of the secant piles as well as areas with shallow bedrock elevations were shotcreted to achieve cost and schedule savings for the Client.
The primary purpose of the secant pile wall was to provide adequate ground water cut-off so that excavation could proceed. The wall also acted as a reten-tion structure, preventing excessive soil movement that may have impacted nearby roads and an active railway line.
The soil conditions encountered were 5m of sand fill underlain by a 5m thick silt layer and a 1 to 2m thick till like material. A sandstone with some siltstone fragmented bedrock was reached between 7.6m and 13.7m below surface. The groundwater level was located at around 2.5m below grade.
Despite the unique challenges involved, the project was completed safely, within specifications, meeting quality targets and to the satisfaction of the Cli-ent.