Vibrocompaction Design and Ground Improvement in Surrey, BC

For a standard design package covering pre-treatment assessment, grid layout, energy parameters, and post-treatment QC planning, project fees generally fall between CA$2,040 and CA$6,270. The range reflects site size, depth of treatment, number of CPT verification soundings, and whether a pre-production test panel with instrumentation is required. This is the engineering design cost; the field execution is a separate construction line item.

Vibrocompaction uses a depth-controlled vibrating probe to densify granular soils in situ, while dynamic compaction drops a heavy weight from a crane. In Surrey's urban areas — particularly near existing structures in Newton or Fleetwood — vibrocompaction generates lower surface vibrations and allows treatment closer to property lines without risk of structural distress. It also reaches greater depths with more uniform results in the thick sand sequences of the Fraser floodplain.

Yes, provided the soil profile is predominantly clean to silty sand with less than 15% fines. The design targets a relative density above 70% in the critical upper layers, verified by CPT before and after treatment. For mid-rise structures, we typically extend treatment to a depth where the cyclic stress ratio drops below the triggering threshold defined in the NBCC 2020 seismic provisions for the Surrey area.

The design QC plan specifies post-treatment CPT soundings at 1.5 m vertical spacing, placed at both grid centers and midpoints between probes. We compare pre- and post-treatment tip resistance and sleeve friction profiles, and check pore pressure dissipation rates. In some cases, supplementary SPT borings are taken for laboratory grain-size confirmation and to correlate with the CPT data. The goal is to demonstrate that the target relative density and tip resistance have been achieved uniformly across the treatment zone.

When fines content exceeds 15%, vibrocompaction efficiency drops because the silt and clay fraction impedes particle rearrangement and drainage. In these cases, the design may need to shift to stone columns or a hybrid approach where the vibroflot is used to install gravel elements that provide both densification and drainage. We identify these transitions during the pre-treatment CPT and grain-size analysis phase so that the ground improvement strategy is adapted before field work begins.