Slurry-supported tunnelling requires a fluid system matched to the machine, ground and groundwater conditions.
In slurry-mode operation, a pressurized liquid medium—commonly a bentonite suspension—can support the tunnel face. This application differs from earth-pressure-balance operation, where conditioned excavated material provides the principal support medium.
Start with the Tunnelling Method Before recommending a bentonite grade, confirm the machine’s operating mode and the intended role of the material.
The term “TBM bentonite” is too broad to define a purchasing specification. Face-support slurry, lubrication slurry and other fluids may have different requirements.
Evaluate the Complete Circuit A tunnelling slurry must function within a connected system of preparation, pumping, excavation and solids separation.
Herrenknecht Separations describes bentonite suspension as a transport medium for excavated soil and identifies separation equipment for treating solids-laden fluids.
Material trials should therefore consider rheology and filtration behavior alongside pumpability and treatment requirements.
Include Representative Ground and Water Fresh-water tests provide a baseline, but groundwater chemistry and excavated fines may alter the fluid.
Evaluate representative soil and water where available. Record changes after contamination and recycling rather than judging the grade only from its initial viscosity.
Fluid formulation cannot compensate for unsuitable pressure control or inadequate separation capacity.
Prepare for Regional Operating Conditions For projects in Africa, the Middle East, Russia and South America, identify the actual mixing temperature, water availability and storage conditions.
Where temperatures vary, establish a preparation procedure that produces repeatable results. Where deliveries take time, coordinate inventory with the project’s consumption and storage capacity.
Specify the Application Clearly A useful inquiry includes the TBM type, ground investigation, water analysis, separation equipment and target slurry properties.
HERMANO offers bentonite samples for construction-fluid evaluation. Provide these details to discuss a grade suitable for project-specific trials.
