Tunnel Business Magazine

JUN 2018

TBM: Tunnel Business Magazine is the market leader for North America. TBM is written for leading professionals in all aspects of tunneling and covers project stories, design elements, contracting strategies, legal issues, new technology and more.

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challenging on the project, at maximum depth and with geology ranging from lake clays to abrasive full-face basalt. Despite the challenges the machine has been able to achieve a project record of 30 m in 12 hours, showing that an EPB can indeed be used in very different conditions. The Importance of TBM Maintenance It is essential to consider the total life cycle of a machine, and in maximizing the efficiency and life of the equipment through good design and maintenance. "I'm a mechanical engineer — if you maintain a car, it will last a very long time. If you don't maintain it, it breaks down. The same can be said f e a proper preventative maintenance schedule will pay dividends," said Wil- lis. "The structure of a is metal — as long as the structure is intact, you can then check on the bearings, conveyor, hydraulics, and other components. You must pay particular attention to com- ponents that are hard to reach. The main bearing is one of those parts that is very challenging to replace during tunneling." At Bangalore, India's recently completed o, iPS rescued and refurbishe om a European manufac- turer, and then operated it for owner Bangalor o Rail Cor- pora C) alongside the project's original contractor. "We found severe wear — the cutterhead was essentially bare; the cut- ters and grill bars had been worn away. We also found a serious crack in the screw conveyor and the flights had been severely worn. een operating for 12 months and had bored 300 m of abrasive ground with insufficiently thorough mainte- nance. It came to a standstill below the main railway lines at a ma- jor Bangalore metro station. iPS were able to build an intermediate shaft and r oint that it could advance into that shaft for further rebuild work including a replacement cut- terhead. Once the rebuild was complete, iPS then trained the crew on the importance of maintenance and inspections. "We showed them how to do regular inspections and interventions, what to look for, and how to prevent significant damage. For example, if you do regular inspections of the cutterhead you can detect cut- ter ring damage early on. With timely replacement one can avoid damage to the hub, put a new disc on, check the seals, and a cutting disc can be reused for a third of the price." etween projects also af- fects equipment life and can minimize the costs of a subsequent rebuild—such as storing components indoors, coating the equip- ment with anticorrosive spray, and making sure the main bearing TUNNELINGONLINE.COM TBM: TUNNEL BUSINESS MAGAZINE // JUNE 2018 C O V E R S T O RY 1 9 The new Robbins cutterhead with back-loading disc cutters provided for the record-setting TBM at Indianapolis, Indiana, USA's DigIndy Tunnels. More than one third (36%) of currently standing TBM world records have been achieved using rebuilt machines.

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