closed-face-wheel mole

tunnel machine

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Last updated

June 24, 2026

Quick Summary

A closed-faced-wheel mole is a type of tunneling machine used in soft-ground excavation. Unlike open-face moles, it can be pressed against the tunnel face while drawing in muck through slots. This design is advantageous because it can be operated even in firm ground, and cutter changes can be performed safely. This machine has been successful in projects like the San Francisco subway, demonstrating efficiency and safety in tunneling through clay and sand layers. The closed-faced-wheel mole operates within a shield and discharges excavated material onto a conveyor belt.1

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tunnels and underground excavations
Soft-ground moles
The closed-faced-wheel mole partly offsets this problem, since it can be kept pressed against the face while taking in muck through slots. Since the cutters are changed from the face, changing must be done in firm ground. This kind of mole performed well, beginning in the…
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The closed-faced-wheel mole partly offsets this problem, since it can be kept pressed against the face while taking in muck through slots. Since the cutters are changed from the face, changing must be done in firm ground. This kind of mole performed well, beginning in the…
Read More