Low mobility (compaction) grouting is the injection of a low slump, mortar grout to densify and reinforce soil or fill subsurface voids. Keller has led the industry in low mobility grouting since developing the compaction grouting technique over five decades ago.

Common Uses

  • Reduce liquefaction potential
  • Decrease settlement
  • Increase bearing capacity
  • Stabilize sinkholes or reduce sinkhole potential
  • Compaction grouting

Technical Details

Low Mobility Grouting densifies 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.

Compaction grouting was developed in the 1950s as a remedial measure for the correction of building settlement. Over the past 25 years, low mobility grouting technology has evolved to treat a wide range of subsurface conditions for new and corrective construction. These include rubble fills, poorly placed fills, loosened or collapsible soils, karst conditions, and liquefiable soils.

Low mobility grouting often offers an economic advantage over conventional approaches such as removal and replacement, or piling, and can be accomplished where access is difficult and space is limited. Low mobility grouting for treatment beneath existing structures is often selected because the low mobility grout columns do not require structural connection to the foundations.