Cutter Soil Mixing (CSM) enhances the engineering properties of soils and reinforces soil masses by mechanically mixing the in situ soils with a binder slurry, typically comprising either cement or bentonite slurry or a combination of the two.

Cutter soil mixing technique illustration

Common uses

Temporary shoring of deep excavations
Cut-off walls to mitigate seepage or contaminant transport
Reduce liquefaction potential
Enhance slope stability
Provide structural support

Process

Cutter Soil Mixing (CSM) is a specialized deep mixing technique used in almost any soil type. The process incorporates cutter wheels, rotating about horizontal axes, and mounted on the end of a Kelly Bar, cutting their way into the soils to form a panel of improved soil that is rectangular in plan. As the cutter head advances, binder slurry is pumped through a nozzle between the wheels and mixed with the in-situ soils. The action of the cutter teeth and cutting fins, combined with the shear plates situated just above the wheels, serves to develop a thoroughly mixed soil mass. Adding binder on the withdrawal stroke, combined with a high rotation speed of the cutter wheels, blends the soils and slurry further and creates a well-mixed in situ product.

Cutter Soil Mixing creates strengthened and stiffened individual soilcrete elements, commonly called panels. Treatment is possible at up to 50m depths using large base carriers; however, typical panel depths are 25 to 35m. Pre-drilling can be used to improve productivity in very dense soils or soft rock. The ease of the process is contingent on soil type, strength, water content, plasticity, and texture.

Advantages

Can be used in almost any soil type