Compaction Grouting

Low Mobility Grouting densify loose granular soils (Compaction Grouting), reinforces fine grained soils, and stabilizes subsurface voids or sinkholes by the staged injection of low-slump, low mobility aggregate grout. When performing soil improvement, an injection pipe is first inserted typically to the maximum treatment depth. The grout is then injected as the pipe is slowly removed in lifts, creating a column of overlapping grout bulbs. The expansion of the low mobility grout bulbs displaces surrounding soils. Compaction grouting increases the density, friction angle, and stiffness of surrounding granular soils. The effectiveness of the improvement can be increased by sequencing the low mobility (compaction) grouting work from primary to secondary to tertiary locations. In all soils, the high modulus grout column reinforces the treatment zone.