Keller has announced that it has undertaken its first project using cutter soil mixing (CSM) in Canada to create a temporary earth retention structure for the basement of a new residential development.
When it’s finished in spring 2019, the Platform development complex in Port Moody, British Columbia residential, retail, commercial and social spaces and a major part of the ground engineering work has just been completed.
Keller performed earth retention and excavation support for a section of the development – 2718 Clarke Street, a 38m-tall by 79m-wide property.
“The ground in this area features deltaic alluvial flow deposits with few obstructions, making it ideal for CSM,” said Keller field engineer Johannes Reinisch. “Developed from diaphragm wall technology, CSM uses two sets of counter-rotating, vertically mounted cutter wheels that cut the surrounding soil and blend the injected cement slurry with the in-situ soil to form soil cement panels.”
The CSM shoring wall was designed as a temporary earth retention structure, anchored to support the maximum excavation depth of almost 11m and embedded in a silt layer to restrict groundwater seeping into the excavation pit. Construction included the supply and installation of almost 90 650mm-thick CSM panels to a depth of up to nearly 16m.
According to Keller assistant project manager Anand Mitchell, using an alternative technique would have taken three times as long. “The cutter tool takes about two hours to do the work of three drill rigs, creating the panels in the ground,” he said.
“Reaching the planned production rate required skilled workmanship to ensure safe completion on schedule,” said Mitchell. “Site logistics, safety protocols, and production sequences needed to be thoroughly planned, reviewed, and executed on each work shift.”
Due to limited storage space on site, delivery of cement and H-piles was timed to coincide with the construction schedule. Keller then completed the installation of 124 H-piles within the CSM panels and finished a week ahead of schedule.
Keller is now scheduled to install two levels of anchors for a separate scope of work on the scheme.