Compaction grouting is a ground improvement technique that densifies the soil by grouting under pressure a network of inclusions.
Presentation and key elements
What is compaction grouting and why do we use it?
Compaction grouting is a ground improvement technique. It is used to stabilize and densify compressible soils, and for liquefaction mitigation. Compaction grouting can also be used as vertical reinforcement elements similar to rigid inclusions.
Basic principle of compaction grouting
The use of a mortar or concrete laterally compacts the soil without vibrations.
Execution of compaction grouting
The treatment involves the injection of a mortar, generally with high viscosity, under pressure and at a controlled flow rate, which displaces the soil around the drilling tool and subsequently compacts it. Compaction ratios for this technique can be quite high and are generally in the range of 6-10%.
Compaction grouting is a quasi-static process with controlled pressure and injection rates. There is therefore no risk of increasing pore water pressure nor generating post-construction settlement.