Sand Compaction † applied to non-cohesive subsoils where the
granular particles are rearranged into a denser condition by poker
vibration.
The crane-suspended vibrating poker is water-jetted into the
ground using a combination of self weight and water displacement
of the finer soil particles to penetrate the ground. Under this
pressure, the soil granules compact to increase in density as the
poker descends. At the appropriate depth, which may be determined
by building load calculations or the practical limit of plant
(generally 30 m max.), jetting ceases and fine aggregates or sand
are infilled around the poker. The poker is then gradually
withdrawn compacting the granular fill in the process. Compaction
continues until sand fill reaches ground level. Spacing of
compaction boreholes is relatively close to ensure continuity and
an integral ground condition.
Soil Stabilisation and Improvement