Rigid inclusions

Soil improvement by means of rigid inclusions (also called compaction grouting columns or grout injected columns) results in a flexible foundation system with controlled settlements. The inclusions are executed with a screw especially designed for lateral soil displacement and injection of grout or concrete with a low strength class. Compaction grouting is used to improve the soil mechanical characteristics of compressible soils and increase the stiffness of the soil mass. The columns control and reduce the largest settlements by transferring the vertical load of the upper structure to the underlying load bearing stratum in which the inclusions are installed.

Construction sequence

1. Placement of the screw head. A lost closing nut tip, located under the screw prevents any penetration of water and / or soil during screwing-in. .

2. The especially designed auger, powered by a hydraulic rotary table with large torque capacity and static down thrust, displaces the soil laterally during the screwing-in phase.

3. Vibration-free screwing-in of the screw with its displacement body up to the requested design depth.

4. During the extraction phase of the auger, grout or concrete with a lower strength class is pumped under controlled pressure through the hollow, central tube into the borehole.

5. Completed rigid inclusion, illustrated with an enlarged head.

Construction chart

Fields of application

• Well adapted to high uniform surface loading with strict settlement requirements (e.g. industrial warehouses, infrastructure projects such as road and railway embankments, etc…).

• Total solutions can be developed in consultation with the research department

Environmental impact

• Vibration-free execution

• Low noise pollution

• Virtually no extraction of soil after the installation of the rigid inclusions, therefore limited removal of spoil resulting in a cleaner working area

• A stable, dry and flat work platform is required.

Technical specifications

• An enlarged head may optionally be realised to improve distribution of the load of the upper structure towards the rigid inclusion

Related projects for this technique

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