In the last 15 years Jet Grouting is the preferred ground stabilization techniques (e.g. excavation pit plugging, underpinning and foundation constructions) in soil conditions ranging from loose sediment up to soft rock structures.
In the Jet Grouting process a cement suspension is injected with high pressure through the jet grouting tool (e.g. injection nozzles) into the soil in the before drilled hole. The cement suspension mixes with the surrounding soil as the Jet Grouting tool string is slowly rotated and retracted from the hole.
The result is a subsurface grout column.(Bild 1).
The application of the Jet Grouting technique raises problems concerning forecasting and controlling of the grout column geometry.
Borehole deviation limits the use of Jet Grouting to a depth of 50 m.
The aim of the EU-aided research project “Navigational Jet Grouting” (NAVIJET) is a technical advancement of the jet grouting equipment and the realization of an integral planning and process monitoring system for improving the product quality. In cooperation with five partners from England, France and Germany, the Institute of Mining Engineering I (BBK1) and the Institut für Bergwerks- und Hüttenmaschinenkunde (IBH) are working on the following topics:
- Model development for the calculation of the penetration depth of the injected cement suspension
- Optimization of the injection process by optimization of the geometry of the injection nozzle
- Development of a quality monitoring system which is able to comprise the profile and volume of the injection body in real time