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VibrocompactionCompacting Loose SandsWhat Is Vibrocompaction?
The probe is first inserted into the ground by both jetting and vibration. After the probe reaches the required depth of compaction, granular material, usually sand, is added from the ground surface to fill the void space created by the vibrator. A compacted radial zone of granular material is created. What Soils Are Suitable?Vibrocompaction is ideally suited for clean sands where the silt content is less than 10 to 15 percent. Soils with appreciable silt content can not be densified by vibration alone. However, the use of gravel backfill with the vibroreplacement (stone column) method extends the range of soils that can be improved to silty and clayey sands, silts and clays. How Much Improvement Is Possible?The degree of densification that can be achieved by vibrocompaction is dependent upon many factors, including:
Relative densities in excess of 85% can be achieved, with relative densities of 70 percent being common. Allowable bearing pressures of up to 8,000 pounds per square foot (psf) are not uncommon with vibrocompaction. Minimal settlement results since the modulus of deformation is often increased to over 1,000 tsf. |