Soils are injected with grouts, the choice of which depends on the nature of the medium to be injected (fissured rock or sand and gravels) and the results desired: imperviousness, consolidation, cavity filling, the jacking-up of buildings.
Grouts may be unstable, stable, liquids or foams, and are characterized by their decantation, setting time, viscosity and rigidity.
They produce their effect either by impregnation or by “claquage”. For the injection of unstable grouts, the final injection pressures must be limited to a high value, whilst for stable or liquid grouts it is the quantity injected that must be fixed in advance.
The applications envisaged relate to:
The treatment of galleries,
cavity filling, and
the jacking up of buildings.
Over-strict specifications lead to disappointing results because of the heterogeneity of soils. Controls must relate to results and not to methods.