The technique was created in the 1970s and 1980s in Japan and Scandinavia, initially to improve the bearing capacity of very soft clay soils. Bachy was a trailblazer in this field, introducing its Colmix® process into Western Europe as early as 1986. Since then, the Deep Soil Mixing technique has been extended to a wide range of soil types and applications.
In practice, this technique consists of mechanically mixing the in-situ soil while incorporating a cementitious material, which is usually made of one or several hydraulic binders such as cement, blast furnace slag, lime, fly ash, etc.
This technique encompasses several different processes:
Deep Soil Mixing has many applications across a broad spectrum of construction projects, including:
Generally speaking, this technique is appropriate for any soil type. The soil/binder mix is a semi-rigid material behaving halfway between natural soil and concrete, and offers improved mechanical and hydraulic properties compared to the original soil.
A durable, semi-rigid material with known mechanical and hydraulic properties
Produces very little spoil (reusable in some cases)
A considerably smaller carbon footprint
Lower production and logistics costs
Saves time spent on preparatory work
All these processes usually involve three stages: mechanical destructuring of the existing soil, incorporation of the mix and homogenisation of the mixture. Very often, all three stages are carried out simultaneously.
The binder mixed with the soil is selected and designed to obtain the hydraulic and/or mechanical characteristics required by the project. Where the technique is used to remediate polluted ground, the binder can be chosen specially to neutralise the pollution.
Once combined, the soil-cement mixture forms either columns, wall panels or continuous trenches.
Since 2005, we have installed more than 2 million m² of cut-off wall on dikes.