A design-build Geostructural Design & Construction company, Schnabel is one of the nation’s premier soil mixing contractors..

Soil mixing is a process of mixing cement grout with soil in-situ (on site) to improve the strength of the soil and reduce its permeability. Soil mixing is used to construct impermeable earth-retaining structures and stable groundwater barriers, while improving the supportive properties of the soil.

Whatever the environment, whatever your operational challenges, Schnabel has the expertise to provide the right soil mixing solution for your unique needs.



As a leading-edge soil mixing contractor, Schnabel knows that proper soil mixing is an essential step in creating durable earth-retention solutions. When done correctly, the mixing process yields a soilcrete mixture that has both increased strength and reduced permeability.

One application for soil mixing is in the construction of earth-retaining structures where a groundwater cut-off is also required. Schnabel typically drills a series of overlapping soilcrete columns to create a continuous groundwater cutoff wall.

Steel piles are typically placed in the soilcrete while it is still wet to improve its strength. The increased strength of the treated ground allows it to span between the piles. The reduced permeability of a soil mix wall allows the excavation to take place under relatively dry conditions with limited draw down of the water table outside the excavation.

Soil mixing can also be used to create an impermeable barrier below the ground surface where no excavation takes place, such as to reduce seepage through a dam or to contain contaminated groundwater. Another use for soil mixing is the improvement of foundation soils to increase their strength and reduce the likelihood of liquefaction during an earthquake.

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soil mixing services

Boston Museum of Fine Arts

Schnabel constructed a cement deep soil mixed (CDSM) wall for the excavation support system at the Boston Museum of Fine Arts in Massachusetts.

soil mixing contractors

Patriots Plaza

Schnabel used several techniques such as deep soil mixing, pressure grouting, and secant piles to provide both excavation support and to impede groundwater flow into the excavation at the Patriots Plaza project in Washington D.C.

Schnabel designed and installed a soil mix wall to support an excavation that was within three feet of the historic Boston Museum of Fine Arts. The low vibrations during installation and increased stiffness of a soil mix wall helped protect the priceless artifacts in the museum. Schnabel worked closely with our client John Moriarty & Associates to ensure project success.

Harry W. Schnabel, P.E., , Boston Museum of Fine Arts Project


Schnabel is the sector’s most operationally efficient Geostructural Design & Construction contractor. We optimize efficiencies by leveraging decades of experience and design/build expertise to innovate processes and approaches that are consistently proven to deliver optimal outcomes for our clients.