High-Pressure Jet Grouting Pile vs. Cement Mixing Pile: Key Differences

When it comes to ground improvement techniques, high-pressure jet grouting piles and cement mixing piles are two commonly used methods. While both involve cement mixing with soil to enhance stability, they differ significantly in working principles, machinery, construction processes, applicable soil conditions, and usage scenarios. Understanding these differences is crucial for selecting the most suitable method for your project.

1. Different Working Principles

Cement Mixing Pile

The deep cement mixing (DCM) pile method uses cement as the primary stabilizing agent. A specialized deep mixing machine forcibly blends soft soil with the cementitious binder at the required depth, hardening the soil to improve foundation strength. This method is highly effective for soft soil treatment and allows for quick post-construction use.

Two Construction Variations:

• Wet Method (Slurry Mixing): Uses cement slurry.

• Dry Method (Powder Mixing): Uses dry cement powder.

High-Pressure Jet Grouting Pile

This technique involves drilling a grouting pipe with nozzles into the soil to a predetermined depth. High-pressure fluid is then ejected, breaking down the soil structure. The fragmented soil mixes with the grout, while some particles are flushed out. As the pipe rotates (360°) and rises, the mixture solidifies, forming a high-strength, water-resistant column.

Construction Variations:

• Single-Fluid, Double-Fluid, or Triple-Fluid Systems

• Spraying Methods: Rotary jetting, fixed jetting, or oscillating jetting.

2. Different Machinery

Cement Mixing Pile Equipment

• PH-5 series deep mixing pile machine

• Auxiliary equipment: Grout pump, slurry mixer, and other cement preparation tools.

High-Pressure Jet Grouting Pile Equipment

• Jet grouting rig

• High-pressure plunger pump

• Air compressor

• Slurry mixer

• Grouting pump

• Dewatering pump

3. Different Construction Processes

Cement Mixing Pile Process

1. Mark pile positions → Position the drilling machine

2. Drill to design depth (using forward circulation)

3. Activate the high-pressure grout pump

4. Reverse circulation lifting while injecting cement slurry

5. Repeat mixing at 0.3m below the working surface

6. Lift drill to surface → Complete pile → Move to next location

High-Pressure Jet Grouting Pile Process

1. Mark pile positions → Position the drilling machine

2. Pilot drilling (reaming) to design depth

3. Seal vertical nozzles → Mix slurry

4. Rotary jet grouting upward to the design top level

5. Cleanup → Relocate

4. Different Applicable Soils & Applications

Cement Mixing Pile

Suitable Soils:

• Soft clay, silt, organic soil, loose sand (without flowing groundwater)

• Typical depth: >5.0m

Applications:

• Retaining walls & waterproof curtains (for deep excavations)

• Composite foundations (vertical load-bearing)

• Mass soil stabilization

• Shape variations: Columnar, wall-like, grid, or block configurations

High-Pressure Jet Grouting Pile

Suitable Soils:

• Mud, silty clay, loose sand, gravelly soil

• Not ideal for soils with large boulders, roots, high organic content, or rapid groundwater flow

• Typical depth: >5.0m

Applications:

• Foundation reinforcement (new & existing structures)

• Deep excavation & subway projects (soil stabilization/waterproofing)

• Used as waterproof curtain walls (fixed/oscillating jetting)

• Combined with retaining piles for seepage control

Conclusion: Which Method to Choose?

Both methods stabilize soil by mixing cement, water, and soil, but:

• High-pressure jet grouting offers higher efficiency & broader applicability but at a higher cost.

• Cement mixing piles are more economical and are often used in shield tunnel portal stabilization.

• Jet grouting is ideal for filling gaps (e.g., between diaphragm walls and stabilized soil).

For optimal results, consider soil conditions, project requirements, and budget when selecting between these two ground improvement techniques.