Jet Grouting tecnique improves soil's mechanical and permebility properties by using high-speed jets of water/cement mixture injection treatement.
Jet Grouting can be advantageous in the following conditions:
- difficult logistic conditions
- confined spaces
- presence of obstacles to cross high-depth treatment with crossing of voids
The jet grouting technique allows improvement to a wide range of soil types. Based on soil erosion, soil erodibility is crucual to the final result. The more consistent the soil to be treated is, the smaller the column diameter is. Therefore, larger columns can be obtained in loose, soft soils and smaller ones in cohesive soils.
Consolidated elements (usually columns) are constructed using small-diameter drilling (3.9'' to 5.5''), by means of light and easy to handle rigs. Jet Grouting is usually performed down to depths of 65.6 ft. to 98.4 ft. However, special projects reaching 3.28 ft. depth have also been realized.
All Jet Grouting techniques uses a preliminary phase of drilling, followed by extraction and rotation at preset values, and simultaneous pumpings of the fluids at high pressure. Depending on the number of the fluids used, the European standards EN 12716 has identified three main techniques:
- SINGLE FLUID, a water/cement mixture is injected to break up and simultaneously mix the soil in-situ.
Diameters usually range from 1.31 ft. to 3.28 ft.
- DOUBLE FLUID, a combination of air and water/cement mix is injected to break up and simultaneously mix the soil in-situ.
Diameters usually range from 2.62 ft. to 8.20 ft.
- TRIPLE FLUID, a combination of water/air jet is used to break up and partially remove the soil in-situ, whereas soil mixing is ensured by a lower water/cement injection.