Slurry Pressure Balance Mode - The Slurry excavation mode provides continuous support to the tunnel face by balancing earth and water pressure in the in-situ soil with a pressurized bentonite slurry. This excavation mode provides continuous support to the tunnel face by balancing the inside earth and water pressure against the slurry pressure of the machine. The ground excavated by the cuttinghead is mixed and accumulated under pressure in the cuttinghead chamber, and is then extracted by a Screw Conveyor. The pressure in the cuttinghead chamber is controlled by balancing the rate of advance of the machine and the rate of extraction of the excavated material by the Screw Conveyor.
