Introduction
Tube-à-Manchette (TAM) grouting has become an essential technique in ground improvement and seepage control. By injecting grout at controlled pressures through sleeve pipes, TAM grouting allows precise strengthening of soil and rock masses. When integrated with deep foundation systems (such as piles, barrettes, and caissons) and retaining structures (diaphragm walls, secant piles, sheet piles), TAM grouting enhances both structural performance and ground stability, particularly in challenging soil and groundwater conditions.
1. Role of TAM Grouting in Deep Foundations
1.1 Load-Bearing Enhancement
- Grouting increases the skin friction along piles and barrettes by improving the surrounding soil strength.
- Strengthened soil reduces settlement and enhances axial load capacity.
1.2 Base Resistance Improvement
- TAM grouting beneath pile tips forms grout bulbs, improving end-bearing resistance in soft or loose soils.
- Beneficial in sandy or gravelly soils with insufficient natural bearing strength.
1.3 Pile Group Efficiency
- Reduces negative skin friction in soft clay layers by stiffening the soil around piles.
- Improves overall group behavior in high-rise and bridge foundation projects.
2. Role of TAM Grouting in Retaining Systems
2.1 Permeability Control
- Creates impermeable curtains behind diaphragm or secant pile walls, controlling groundwater seepage.
- Enhances the hydraulic efficiency of cutoff walls in deep excavations and dam foundations.
2.2 Earth Pressure Reduction
- Stiffened soil behind retaining walls reduces lateral earth pressures.
- Prevents excessive wall deflections and enhances structural serviceability.
2.3 Structural Integration
- Grouting can be combined with anchors and soil nails, providing composite action with retaining walls.
- Improves slope stability in excavations subjected to both water pressure and soil loading.
3. Applications in Practice
- Piled Raft Foundations: TAM grouting beneath pile tips increases settlement control in high-rise buildings.
- Diaphragm Walls in Metro Projects: Used for groundwater cutoff and soil strengthening around deep stations.
- Secant Pile Walls in Urban Excavations: Prevents leakage and improves lateral resistance in mixed soils.
- Bridge Foundations: TAM grouting around pile groups in riverbeds controls seepage and scouring effects.
4. Advantages of Integration
- Improved Bearing Capacity: Strengthens soil-pile interaction.
- Reduced Settlement: Critical in urban areas with sensitive structures.
- Seepage Control: Essential in excavations and water-retaining structures.
- Flexibility: Adaptable to different soil conditions and structural requirements.
5. Limitations and Challenges
- Clays: Low penetrability limits grout effectiveness unless fissures exist.
- Groundwater Flow: Risk of grout washout if not carefully managed.
- Cost and Time: Requires careful planning and monitoring compared to conventional methods.
- Execution Quality: Dependent on pressure control, grout mix, and drilling precision.
Conclusion
The integration of TAM grouting with deep foundations and retaining systems significantly enhances load-bearing performance, settlement control, and groundwater management. Its effectiveness, however, depends on careful soil investigation, grout selection, and execution quality. When properly applied, TAM grouting offers a sustainable and reliable solution for modern geotechnical engineering challenges, particularly in urban excavations, underground structures, and critical infrastructure projects.
