Techniques.

Soil mixing improves the characteristics of soil in situ by mixing it with a grout, usually cement slurry. This technique requires no prior transformation of materials: the soil in situ is not extracted and is used as it is. Since it uses the soil in situ, soil mixing involves little excavation and therefore little earth has to be moved and less machinery is needed. Since it also requires less grout than other soil reinforcement techniques, soil mixing is environmental friendly.

Tool for implementing the wet method

Tool for implementing the dry method

Soil mixing is done in three stages:

• destructurating the soil in situ,
• injecting the grout,
• mixing.
The dry method is used for soils with high water content: a tool injects the grout in powder form and mixes it with the soil in situ.

The wet method is used for soils with low water content: a tool injects the grout in slurry form under low pressure and mixes it with the soil in situ.

© KELLER

Soil mixing is a simple technique, constantly being improved. It is easily adapted to the structure to be built and different soils.

IT THEREFORE HAS MANY APPLICATIONS:

- retaining terrain
- reducing settlement beneath constructions
- watertightness, to confine polluted soils for example
- soil stabilization, particularly to prevent liquefaction during earthquakes.

This technique allows you to quickly realize and easily walls in the ground.
A slicer is specially equipped to perform soil mixing.

© SOLETANCHE-BACHY

Realization of waterproof walls for a dike
© Cédric Helsly pour Soletanche Bachy

Reinforcement work under a railway platform
© Sandrine VILLAIN / Image&son-cnam

A specific tool is inserted into a thin tube enabling drilling between the track’s sleepers.

When it emerges from the tube, the tool opens and bores soil mixing columns of larger diameter.

Operation of the soil mixing tool © Soletanche Bachy

© Romain Secco