Jet grouting is a general term used by grouting contractors to describe various construction techniques used for ground modification or ground improvement. Grouting contractors use ultra high-pressure fluids or binders that are injected into the soils at high velocities. These binders break up the soil structure completely and mix the soil particles in-situ to create a homogeneous mass, which in turn solidifies. We have completed many jet grouting jobs in Turkey and outside of Turkey.
This ground modification / ground improvement of the soil plays an important role in the fields of foundation stability, particularly in the treatment of load bearing soils under new and existing buildings; in the in-depth impermeabilization of water bearing soils; in tunnel construction; and to mitigate the movement of impacted soils and groundwater.
The various injection grouting techniques used by grouting contractors for ground improvement / ground modification can be summarized as follows:
Permeation: Grout is injected into the soil at low pressure and fills the voids without significantly changing the soil’s structure or volume. Wide varieties of binders are used with this grouting technique. The choice of the binder is dictated mainly by the permeability of the soil. [Generally, water and cement mixtures are used where the coefficient of permeability is greater than 1 x 10-2 cm/sec. More expensive resin-based grouts are used for permeabilities as low as 1 x 10-6 cm/sec. Soils with permeabilities less than 1 x 10-6 cm/sec are normally not groutable by permeation.]
Compaction Grouting: A highly viscous grout with high internal friction is injected into a compactable soil. The grout acts as a radial, hydraulic jack and physically displaces the soil particles; thus achieving controlled densification.
Claquage: Grout is injected into the soil at a high pressure through a special valved tube, thereby hydrofacturing the soil. The resulting fissures are filled with the grout and the surrounding soil is modified to create a densified mass.
Jet Grouting: This system differs substantially from the other ground improvement or ground modification techniques – it breaks up the soil structure completely and performs deep soil mixing to create a homogeneous soil, which in turn solidifies. The jet grouting technique can be used regardless of soil, permeability, or grain size distribution. In theory, it is possible to improve most soils, from soft clays and silts to sands and gravels by jet grouting. Although it is possible to inject any binder, in practice, water-cement mixtures are normally used. Where impermeabilization of the soil is required, water-cement-bentonite mixtures are typically used.