Stone Columns with Vibroflot
Project key figures:
206 Vibro Replacement Dry Bottom Feed Stone Columns
3380lm of Stone Columns
The Fraser Surrey Docks was constructing a new temporary office building.
The site’s subsurface stratigraphy consisted of the following:
- Approx. 2m of compact to medium dense sand fill with some silt and gravel;
- Underlain by 11m of soft to firm silty clay/silty sand;
- Underlain by 7m of medium to dense sand susceptible to liquefaction.
Groundwater was encountered at approximately 2m from the ground surface.
Vibro Replacement Stone Columns densification was required beneath the new building in order to prevent settlement caused by soil liquefaction in the event of an earthquake.
Menard Canada utilized dry-bottom-feed stone column installation techniques, which was the preferred method of the General Contractor. Stone Columns were installed at 20m depth on a regular grid pattern and 13m in between stone columns to meet the specified CPT tip resistance performance-based requirements.
Densification work began with an initial trial area consisting of 20 stone columns to assess the effectiveness of the proposed methods and stone column spacing. Production work applied similar methodologies to those proven successful in the trial area.