Single-auger Large-diameter DSM

For Large Diameter, homogenous Column Improvement with RAS Column

RAS Column is an advanced deep soil mixing method based on mechanical soil mixing technology to produce soil-cement column of 1.4 to 2.5m diameter.

The mixing head is equipped with the counter rotation mechanism where the bottom auger and mixing blades rotate clockwise while the upper mixing blades rotate counter-clockwise.

This unique mechanism efficiently breaks and mixes in-situ soil with cement-based reagents, producing more homogenous and higher quality soil-cement columns.  It completely eliminates the "turning together" problem, often encountered by conventional mechanical soil mixing methods, that cohesive soil co-rotates with the mixing head, causing insufficient mixing and unexpected deficiency of columns.  

RAS Column efficiently improves foundation soil of building and civil engineering structure to increase bearing capacity and prevent liquefaction.


  • Applicable to a wide range of soils, providing excellent quality improvement
  • Large diameter column improvement of diameter of 1.4m to 2.5m.
  • Uniform mixing and homogenous product quality due to counter-rotation mechanism
  • Computer-based control and monitoring system ensures quality improvement
  • Improvement efficiency in product strength and production speed saves on cost
  • Flexibly adaptable to site-specific improvement requirements
  • Low noise and low vibration system

Construction Sequence

Setup Penetration Churning Completion

Position the rig at a pile position

After passing dry excavation zone, start injecting slurry.  Drill down and mix with in-situ soil to a specified depth. Move the head up and down to mix thoroughly so that each part of the soil receives the pre-defined number of cuts by mixing blades. Withdraw and complete a soil cement column.

3D-ViMa system

Three-dimensional Visualized Management System

3D-ViMa is integration system of construction management including quality control information, design drawing and GPS information of construction that can visualizes 3D model of the work execution.  This system is available for RAS Column method.

Alternative Technologies

Multi-auger DSM

DSM is an in-situ soil mixing technology that mixes existing soil with cementitious materials using mixing shafts consisting of auger cutting heads, discontinuous auger flights, and mixing paddles.  The mixing equipment varies from single to eight shaft configurations depending on the purpose of the deep mixing. 


Soil Mixing Wall

RSW mixes in-situ soils with cement grout or other reagents slurries using a multiple shaft auger to produce continuous subsurface soil-cement walls for excavation support, groundwater or underground pollutants control, or ground reinforcement.  The soil-cement is usually reinforced with steel H-piles when used for excavation support along with groundwater control.

Shallow Soil Mixing

SCM is a method to mechanically mix in-situ soil with cement powder or slurry. SCM provides two different mixing equipments, Rotary Blender and Bucket Mixing, to be selected depending on improvement objectives and depth. The unique mixing mechanism provides efficient, cost effective and quality improvement. Larger plant is not necessary. 

Raito, Inc.

32960 Alvarado-Niles Rd., Suite 680, Union City, CA 94587

Phone: +1-510-259-9900  Fax: +1-510-259-9901

Toll Free: 1-866-DEEP-MIX (1-866-333-7649)