CI-CMC / CI-CMC-HA Methods (Large-diameter, superior quality deep mixing method / Large-diameter, low displacement deep mixing method suited to hard ground)

Deep Mixing Methods that Deliver Large-diameter, High Quality Improvement Columns

The CI-CMC and CI-CMC-HA methods are deep mixing methods that form large-diameter high quality improvement columns through the development of an “ejector discharge” device that uses compressed air to spray slurry as a mist.
Displacement in the surrounding ground is greatly reduced, allowing implementation close to existing structures in urban areas. Large-volume implementation maintaining high quality reduces costs.

The low displacement CI-CMC method (pile diameter 1,600mm x 2 pipes) was newly listed in the 2017 Ministry of Land, Infrastructure, Transport and Tourism publication of civil engineering quantity standards as a slurry mixing, twin-axis implementation (displacement minimizing type) method of 1,600mm pile diameter.

New civil engineering technology2017年1月 (財)先端建設技術センター 建設技術審査証第2804号
NETIS registeredQS-160049-A(HA)


  • High quality large-diameter columns

    Improved mixing effectiveness delivers large-diameter highly uniform columns.

  • Outstanding driving capability

    Greater driving capability makes mixing possible in ground where penetration resistance is high.

  • Low displacement method

    The effect of using compressed air significantly reduces displacement in surrounding ground.

  • HA: Implementation possible in hard ground

    With more advanced mixing blades, implementation possible from hard ground (N value 50) to soft soil (N value 15).

  • HA: Reduced costs and shortened schedules

    No advance boring is needed in hard ground, reducing costs and shortening schedules.

  • HA: Consistent strength in improved columns

    Controlling the volume of compressed air used in ejector discharge limits strength variation in improvement columns.

  • New Visios-3D® implementation management system

    Visualizing implementation status, following record files and CIM (Concrete Information Modeling) allows mapping as 3D model.

Implementation Method


  1. Positioning / Rig set at required position
  2. Improvement agent discharge and penetration mixing delivers continuous penetration as improvement agent is discharged
  3. Depth check, tip treatment / After checking that the bearing layer has been reached, discharge is stopped for tip treatment.
  4. Withdrawal mixing / During withdrawal, mixing blades are rotated in the opposite direction
  5. Column completion / Column is formed up to ground surface and rig moved to next position.

Improvement design


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