Physical Model Testing of Compaction Grouting in Cohesionless Soil

Preliminary results of small-scale model compaction grouting tests performed in a geotechnical centrifuge are presented. The soil response to a one-stage grout bulb injection in dry uniform sand was examined at various prototype depths, and the effects of grout composition on grout bulb development and shape and on soil response are evaluated. Preliminary results indicate that the shape of the injected grout bulb is a function of overburden pressure. For specific grouting conditions, there is a maximum size that the grout bulb will achieve. Observed soil deformations were similar to those observed in models of deep uplift anchors. The addition of either clay or flyash to the grout mix reduced the ability to sustain high injection pressures.