TBM Sealing Systems: Main Drive, Articulation and Tail Seals for Leak-Tight Drives

A TBM’s sealing system is a three-part defense. Main drive seals protect the main bearing and gearbox from cutterhead pressure and fines; articulation seals absorb shield articulation and differential loads; tail seals, usually wire brush and grease-injection rows, close the gap behind the erector. In soft and karst ground, each must resist abrasive slurry and sudden water inflow. Rubber-metal composite construction gives the elasticity to follow movement and the metal casing to hold tolerance under pressure.

Wear is rarely caused by one factor. Abrasive fines, high water pressure, heat, degraded grease, shaft run