Introduction
Tube-à-Manchette (TAM) grouting is a precision ground improvement method that relies heavily on the appropriate selection of grouting materials and controlled injection techniques. The effectiveness of TAM grouting in strengthening soil and rock masses, as well as reducing permeability, depends on matching grout properties and injection methods to ground conditions. This article discusses the commonly used materials and injection techniques in TAM grouting operations.
1. Grouting Materials Used in TAM Grouting
a) Cement-Based Grouts
Ordinary Portland cement (OPC)
Microfine and ultrafine cement
Cement–bentonite mixtures
Applications: Coarse soils, fractured rock, permeability reduction, and strength improvement.
b) Chemical Grouts
Sodium silicate
Acrylate and acrylamide grouts
Polyurethane resins
Applications: Fine sands, silts, and very low-permeability soils requiring permeation.
c) Suspension Grouts
Cement suspensions with additives
Bentonite-based suspensions
Applications: Void filling and seepage cut-off in rock fissures and coarse soils.
d) Additives and Admixtures
Plasticizers to improve flow
Accelerators or retarders to control setting time
Anti-bleeding agents for stability
These enhance grout performance and durability.
2. Injection Techniques in TAM Grouting
a) Stage-Wise Injection
Grouting carried out in stages along the borehole
Double packers isolate individual injection zones
Ensures uniform treatment and controlled grout spread
b) Repeated (Multiple) Injection
Rubber sleeves allow multiple injections at the same point
Enables refinement of grout distribution
Compensates for grout loss or shrinkage
c) Pressure-Controlled Injection
Injection pressure adjusted based on soil and rock conditions
Prevents hydraulic fracturing or ground heave
Ensures permeation rather than displacement
d) Low-Flow Injection Technique
Controlled flow rate to allow gradual grout penetration
Suitable for fine-grained soils
Reduces risk of surface disturbance
e) Grout Take Monitoring
Continuous recording of grout volume and pressure
Helps assess soil response
Guides decision on further injections
3. Injection Equipment Used
Grout pumps with pressure control
Double packer systems
Pressure gauges and flow meters
TAM pipes with rubber manchettes
4. Selection Criteria for Materials and Techniques
Selection depends on:
Soil type and permeability
Groundwater conditions
Required strength and permeability reduction
Environmental and safety considerations
5. Quality Control during Injection
Monitoring pressure–volume relationship
Observation of refusal criteria
Post-grouting verification tests
Quality control ensures effective ground improvement.
Conclusion
The success of TAM grouting largely depends on the careful selection of grouting materials and precise injection techniques. Cement-based and chemical grouts, combined with controlled, stage-wise, and repeatable injection methods, allow effective treatment of complex ground conditions. Proper material selection and injection control ensure improved strength, reduced permeability, and long-term stability.
