Mass Soil Mixing, (MSM) or mass stabilisation, is performed with a horizontal axis rotating mixing tool positioned on the end of a track hoe arm. Cementitious binder can be added to the ground eitherpneumatically as a dry powder or hydraulically as a cement slurry. The binder is injected into the soil through the mixing tool via a feed pipe, which is attached to the track hoe arm. 

Common Uses

  • Increase bearing capacity
  • Decrease settlement
  • Increase global stability
  • Encapsulate contamination

Technical Details

Mass Soil Mixing is a ground improvement technique that improves soft or loose soils, by mechanically mixing them with either wet grout or dry cementitious binder to create soilcrete.

The mass soil mixing process is typically constructed in pre-defined ‘cells’ of the order of 4m x 4m in plan area. Commonly the cells are mixed adjacent to others to form a 100% mass stabilised zone, all with a designed strength and stiffness. Mass soil mixing is low vibration, quiet, and uses readily available materials. This process is often used in high groundwater conditions and has the advantage of creating almost no spoil for disposal.

Soils vary widely in their ability to be mixed, depending on the soil type, strength, water content, plasticity, stratigraphy, and texture. Organic soil and peats can often be stabilised, but laboratory testing is always recommended prior to design. With Mass soil mixing, treatment is possible to depths up to 5m to 6m. Large obstructions are pre-excavated to remove ahead of the soil mixing process. 

Pre-production laboratory testing is used to determine the mix methodology, energy, and binder content. Keller has developed proprietary equipment and software for the real-time control and monitoring of mixing parameters during the mixing process. Samples of the soilcrete are taken of during producted and cured in a controlled environment for testing.