Jet Grouting is a mix-in-place construction process using a high pressure jet of fluid to break up and loosen the ground, and mix it with a binder.
Using a 100-200mm diameter hole drilled to the required depth, Jet Grouting can be executed at specific elevations. The result is a vertical or inclined soil-cement material reaching up to 10 feet in diameter and 10MPa compressive strength.
In a single jet configuration, the jetting fluid is a grout which performs the three functions of loosening the soil, removing the excess material, and providing the binder.
A significant proportion of the kinetic energy of the jet is lost through friction in the soil suspension and the excess material may become too viscous to rise freely to the hole collar.
If the high velocity grout jet is sheathed in a cone of air, the radius of action of the jet in the same soil is substantially increased.
In the double jet configuration, the air improves performanceby removing in situ soil by acting as an air lift.
In the triple jet set-up, soil loosening and removal is carried out by both water and air jets independently of the incorporation of the binder. The binder is delivered simultaneously by a jet of low pressure grout (at a few MPa) emerging from a lower nozzle.
The high pressure pump and circuit in the triple jet configuration carries only water. There must also be a second, low pressure grout pump, and a three-line drill string.