The compaction of a loose soil or a loose backfill can be achieved at high depth by penetration of a vibrator.

In granular soils, this penetration results in a liquefaction of the surrounding soil and a quasi immediate settlement.

Further to the results of a trial zone, Menard defines :
- the vibrator frequency
- the power of the vibrator
- the requested period of vibration for each different soil layer
 

PASIR PAJANG CONTAINER TERMINAL (Singapore)

In 1996, Menard was awarded the soil improvement works of a reclamation area made of hydraulic fill on a depth of about 10 m. The aim of this soil improvement was to densify the hydraulic backfill, increase the bearing capacity and reduce the liquefaction potential.

The technical solution adopted by Menard was a combined treatment made of dynamic compaction for the first 5 m and vibroflotation for the layer 5 to 10 m.

The acceptance criteria defined by the client was a value of qc higher than 15 MPa over the 10 m to be densified. A geotechnical campaign made of 46 CPTs before the works and 60 CPTs after the works has shown the improvement of the hydraulic backfill and has confirmed this acceptance criteria. .