TBM Sealing Systems: Main Drive, Articulation and Tail Seals in Mixed Ground

In Middle East metro, road and utility drives, TBMs rarely meet clean, uniform geology. Sand and rock mixed-face conditions alternate between free-running abrasive sand and blocky, fractured rock, so cutterhead torque, thrust and shield articulation all cycle hard. That load cycling lands directly on three seal families: the main drive seal package, the articulation (shield) seals, and the tail seal brushes and grease system. Each has a different duty, and each fails differently in desert ground.

Main drive seals are typically rubber lip seals or wire-brush seal packages with metal casing, running in grease against a rotating cutterhead flange. Wear is driven by abrasive fines migrating into the seal gap, pressure spikes from face support, shaft deflection and contaminated grease. Articulation seals are composite rubber-and-metal rings that must handle articulation angle plus external water pressure. Tail seals rely on wire brushes and pumped grease to hold back grout and groundwater behind the segment ring.

The practical rule: monitor grease consumption, seal-gap leakage and grease condition trends, not just calendar hours. Rising consumption or gritty grease means inspect early, before fines reach the main bearing. Keep a seal and brush kit on site sized to the drive, and buy spares factory-direct — OUSUN in Deyang supplies main drive seals, articulation seals, tail brushes and EPB/slurry spares in roughly 2-4 weeks, interchangeable with common machine builds. Contact [email protected].