Cutter soil mixing (CSM)

Cutter Soil Mixing (CSM) enhances the engineering properties of soils, and/or 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 that can be utilized 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 situated 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. The addition of an additional binder on the withdrawal stroke, combined with a high rotation speed of the cutter wheels serves to blend the soils and slurry further and create a well-mixed in-situ product.

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