Next Generation of Hybrid TBMs for Mixed Ground

The use of hybrid TBMs in a mixed and unpredictable underground environment is increasing. This report concentrates on the advances achieved by hybrid TBMs, focusing on what is likely the most common type: A cross between a hard rock single shield TBM and an EPB.

In a mixed and unpredictable underground environment the increasing use of hybrid TBMs is one that goes with the territory. Where multiple machine types might have once been used for different sections of rock and soft ground, a hybrid machine can excavate the entire tunnel. New designs are making this versatile take on tunnelling more efficient, even at larger diameters of 10 m or more.

For the purposes of this article, the focus will be on what is likely the most common type of hybrid machine: a cross between a hard rock single shield TBM and an EPB. Typically these TBMs bore tunnels with...

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