Dry soil mixing is used to improve the engineering properties of high moisture content clays, peats, and other weak soils by mixing a suitable binder in situ to construct soil-cement elements (soilcrete).
- Increase shear strength
- Reduce compressibility
- Reduce permeability
- Lowers liquefaction potential
- Immobilize contaminants
Dry soil mixing is performed by mixing the soil in situ with dry, cementitious binder to create soilcrete elements. The construction of columns begins with inserting a drill string with radial mixing paddles into the soil. The tool cuts the soils while being inserted to prepare for mixing. When the tool reaches the target depth, the cementitious binder is conveyed to the tool, where it is mixed with the soil as it is retracted from the ground.
This process creates individual columns of soilcrete or overlapping rows of columns with a designed strength and stiffness. Benefits of this technique includes low vibration, clean working areas, quiet process, and uses materials that are not difficult to obtain. However, it is best suited for soils that contain moisture contents greater than 60% and close to the liquid limit.
Soil samples are typically obtained from the proposed treatment area and pre-production bench scale testing is typically performed to establish a suitable binder content. All soil mixing parameters are recorded and controlled by proprietary real-time data acquisition system installed on the mixing rig.