Marathon Machines

Quelle/credit: Robbins

Two of the six Robbins TBMs for China’s Liaoning NOW project are seen during shop assembly. Abrasion resistant wear plating is clearly visible on the top and bottom cutterhead pieces to aid in long distance excavation

Quelle/credit: Robbins

Workers in the Liaoning T5 tunnel have installed McNally slats, seen here in the tunnel crown, in more than 50 % of the tunnel

Quelle/credit: Robbins

The abrasion-resistant wear bands, made of Stellite, can be changed in the tunnel in the unlikely event of excessive wear. To change the seal location in the tunnel (illustration on the right), the seal is moved axially relative to the wear band. The spacer between the seals can be relocated so that wear bands do not have to be changed at the same time as the seals, effectively doubling the life of the wear band

Quelle/credit: Robbins

The Robbins machine at T5 has the highest rates of advance and best cutter wear on the project, averaging 675 m per month and 1300 m³bored per cutter

Quelle/credit: Robbins

Cutterhead design to optimize regular cutter inspections and cutter changes is critical for long distance TBM tunneling

Quelle/credit: Robbins

Close monitoring of fluids and oils, in addition to regular maintenance, are key pieces to keeping TBMs operating over long distances

Quelle/credit: Robbins

Robbins continuous conveyors are operating behind all eight machines at the Liaoning NOW project

Quelle/credit: Robbins

A member of the Robbins Field Service team inspects the gripper of one of the Liaoning NOW Main Beam TBMs

Quelle/credit: Robbins

Today’s Tunnel Boring Machines (TBM) are often required to bore longer tunnels in harder rock at a faster pace – a trio of challenges that can be daunting for any contractor. With the proper design, operation, and maintenance, however, modern TBMs are very capable of reaching their 10 000-hour design life or more. TBMs in the industry today have already accomplished the feats of boring upwards of 50 km on multiple tunnels over decades, and of completing single TBM drives totaling 27 km. With new capabilities, even greater feats may be possible.

From abrasive rock to fault zones to water inflows, geologic challenges become more common as tunnel lengths increase. In rock tunnels over 15 km long, a host of challenges may meet a TBM, requiring a versatile design. General wear and tear is an issue on machines boring long stretches of tunnel, and thus minimization of downtime is key. In order to counteract these challenges, a number of design features can be added during the manufacturing process, and these, combined with regular maintenance and well-designed logistics during tunneling, can result in TBMs lasting for the tunnel length and...