Introduction
Ground improvement techniques play a crucial role in modern geotechnical engineering, especially in urban construction, tunneling, and foundation stabilization. Among the most widely used methods are jet grouting, permeation grouting, and compaction grouting. Each method has unique principles, applications, advantages, and limitations. This comparative study highlights the differences and overlaps between these three techniques to guide engineers in selecting the most appropriate solution for soil stabilization projects.
1. Fundamental Principles
- Jet Grouting: High-pressure jets erode and mix in-situ soils with cementitious grout, creating soilcrete columns or panels with improved strength and reduced permeability.
- Permeation Grouting: Low-viscosity grout is injected into permeable soils without disturbing the soil structure, filling voids and binding particles.
- Compaction Grouting: A stiff, low-mobility grout is injected under pressure, displacing and densifying surrounding soils to increase bearing capacity and reduce settlement.
2. Suitable Soil Conditions
- Jet Grouting: Applicable to almost all soil types, including clays, silts, sands, and even gravels. Particularly effective in mixed or challenging soils.
- Permeation Grouting: Best suited for coarse, permeable soils such as sands and gravels where grout can permeate voids. Ineffective in silts or clays.
- Compaction Grouting: Most effective in loose granular soils (sands, silty sands) and collapsible soils where displacement and densification are feasible.
3. Applications
- Jet Grouting
- Excavation support (cutoff walls, bottom plugs)
- Seepage and groundwater control
- Underpinning and foundation strengthening
- Liquefaction mitigation
- Permeation Grouting
- Seepage control in permeable soils
- Void filling in masonry structures and tunnels
- Stabilization around sensitive structures without soil displacement
- Densification of coarse soils
- Compaction Grouting
- Settlement control beneath structures
- Increasing bearing capacity of weak soils
- Mitigation of sinkholes and voids
- Liquefaction resistance in sandy soils
4. Performance Characteristics
| Parameter | Jet Grouting | Permeation Grouting | Compaction Grouting |
| Soil Type | Universal (clays to gravels) | Coarse, permeable soils | Loose granular soils, weak layers |
| Soil Structure Disturbance | High (erosion + mixing) | Minimal (fills voids) | Moderate (soil displacement) |
| Column/Zone Formation | Soilcrete columns or panels | Grouted voids between particles | Grout bulbs and densified zones |
| Strength Gain | High | Moderate (depends on soil-grout bond) | High (due to densification) |
| Permeability Reduction | Significant | Moderate to high (depends on grout penetration) | Limited |
| Settlement Control | Excellent | Limited | Excellent |
| Seismic Improvement | Very effective | Moderate | Effective for sandy soils |
5. Economic and Environmental Considerations
- Jet Grouting:
- High cost due to specialized equipment and grout consumption.
- Versatile and reliable but energy-intensive.
- May generate spoil requiring disposal.
- Permeation Grouting:
- Economical in permeable soils due to low material requirements.
- Environmentally friendly if non-toxic grouts are used.
- Not effective in fine-grained soils.
- Compaction Grouting:
- Moderate cost with minimal excavation.
- Environmentally favorable due to low material use and reduced spoil generation.
- Suitable for projects requiring minimal disruption to surroundings.
6. Advantages and Limitations
- Jet Grouting
- Versatile in all soil types
- High strength and permeability control
- High cost and complexity
- Requires disposal of spoil material
- Permeation Grouting
- Preserves soil structure
- Economical in sands and gravels
- Limited to coarse soils
- Less effective for major load-bearing improvements
- Compaction Grouting
- Excellent for settlement control
- Minimal disruption to existing structures
- Limited to loose granular soils
- Not suitable for dense or impermeable soils
Conclusion
Jet grouting, permeation grouting, and compaction grouting are complementary ground improvement techniques rather than competing ones.
- Jet grouting is the most versatile, suitable for complex soil profiles and projects requiring strength and permeability control.
- Permeation grouting is cost-effective and efficient in coarse-grained soils where grout can penetrate voids without disturbing soil fabric.
- Compaction grouting excels in settlement control and densification of loose soils with minimal disturbance to existing structures.
The choice of method should be based on soil conditions, project requirements, economic considerations, and environmental impact. In many modern projects, a hybrid approach that combines these methods is used to achieve optimal ground improvement.
