• Background
• Methods

Compaction Grouting utilizes a thick, cementitious mass, designed to remain together within the soil matrix. Generally, there is a distinct interface between the soil and grout material. The most improvement can be achieved in granular, alluvial soils or any highly permeable soil matrix that can be mechanically compacted. The technique is most effective in soils of low density which can be consolidated and densified by volume reduction. The most improvement will be attained within the weakest soil zones and the mass will be irregularly shaped. Most types of soil can be improved, however the degree of effectiveness will vary depending on the in-situ conditions. Clay based soils with low permeability react dramatically different than a cohesionless, loose fill material. 

The 1980 ASCE Grouting Committee1 defined compaction grout as: "Grout injected with less than 1 in. (25mm) slump. Normally a soil-cement with sufficient silt sizes to provide plasticity together with sufficient sand sizes to develop internal friction. The grout generally does not enter soil pores but remains in a homogeneous mass that gives controlled displacement to compact loose soils, gives controlled displacement for lifting of structures, or both."