1. Positioning. A crane or tower suspends the mixer to the designated pile position and centers it.
2. Pre-mixing and sinking. After the cooling water circulation of the deep mixer is normal, start the motor and release the crane wire rope so that the mixer sinks while mixing and cutting soil along the guide frame. The sinking speed is controlled by the current monitoring meter so that the working current does not exceed 70A.
3. Prepare cement slurry. After the mixer has sunk to a certain depth, begin preparing cement slurry according to the designed mix proportion, and pour the cement slurry into the hopper before grouting.
4. Lift, inject slurry, and mix. After the mixer sinks to the design depth, start the grout pump to inject cement slurry into the foundation while spraying and rotating, and at the same time lift the mixer strictly according to the lifting speed determined by the design.
5. Repeat up-and-down mixing. When the deep mixer is lifted to the top elevation of the designed reinforcement depth, the cement slurry in the hopper should be exactly emptied. To make the soft soil and cement slurry mix evenly, the mixer may be rotated and sunk into the soil again, and after reaching the designed reinforcement depth, the mixer is rotated and lifted out of the ground.
6. Cleaning. Inject an appropriate amount of clean water into the hopper, start the grout pump, and clean the hopper, all pipelines, and the mixing head.
7. Relocation. Repeat steps 1 to 6 above to construct the next pile.
Because the top of the mixing pile and the part in contact with the foundation or pile cap of the superstructure are subjected to relatively large forces, slurry can also be injected once more within 1.0 m to 1.5 m of the pile top to increase its strength.