JACSMAN (Cross jetting type composite mixing method)

Combining conventional mechanical mixing and high-pressure jet mixing.

This method combines the merits of conventional mechanical mixing with high-pressure jet mixing. It forms soil cement blocks leaving no unimproved part.

New civil engineering technologyJuly 1999 Japan Institute of Country-ology and Engineering (JICE), 1st Technology Development Award

Features

Cross jet injection

With the development of cross jet injection, because the jet mixing range is limited compared to regular high-pressure jet mixing methods…

  • The diameter of the improvement columns can be carefully controlled without any effect from the ground
  • Unconfined compression strength of the improvement columns can be freely selected within the standard range of 0.2-3.0MN/m
  • The significantly improved mixing performance gives highly efficient implementation, and uniform columns can be formed.

Composite mixing

Compared to regular mechanical mixing methods, with composite mixing…

  • Installation close to existing structures or between improvement columns can be achieved reliably and easily
  • Large section (more than 4 times the conventional) improvement columns can be formed.
  • By stopping the cross jet injection the diameter of the improvement column can be changed at any depth as required.

Implementation Method

Procedure

  1. JACSMAN rig centered on required position
  2. JACSMAN blades rotated for ground penetration (low pressure slurry discharged as needed)
  3. Check made that prescribed depth has been reached
  4. Compressed air and ultra high pressure hardening agent are cross injected from JACSMAN blade tips, and after injection at set position withdrawal begins. (low pressure slurry discharged as needed)
  5. Checks made that prescribed heights have been reached for mixing.
  6. Rig moved to next improvement point.