When civil engineering works require soil improvement to build new structures or to restore the existing ones Jet Grouting is applied.
Soil improvement consists in modifying and increasing the mechanical characteristic, the compressive strength, the modulus of elasticity and in the meanwhile decreasing the permeability of the natural soil. Jet Grouting is a modern, fast and effective method applied in soils and in weak rocks for the creation of deep foundation elements.
With Jet Grouting, soil is mixed in site directly with the stabilizer (usually a water/ cement admixture) which is injected at very high pressure (300 Bar al least). The jet stream, coming out from the nozzles located on a specific “monitor”, destroys the natural soil structure and creates a mixing effect between ground and stabilizer.
With Jet Grouting it is possible to treat a broad range of grounds included between gravel and clay. The main difference of Jet Grouting respect to the traditional injection methods is that with Jet Grouting the necessary quantity of stabilizer con be established before the job-site starting, so the final result as for strength and permeability and therefore costs can be defined and estimated a priori.
Jet Grouting techniques are employed in a wide range of cases such as:
• Underpinning of existing structures;
• Diaphragm walls for:
a) Dam and cofferdam cut-off walls;
b) River embankments structural and waterproof cut-off walls
c) Box shape underground structures.
• Diaphragm walls gaps repairing• Structural and/or waterproof bottom plugs.
• Tunnel consolidation:
a) Umbrella type consolidation;
b) Consolidation of the excavation surface.
• Slope consolidations: installation of strand anchors and/or
• Launch and arrival shafts for TBM.