Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Tunnellers shape up for exciting future

TUNNEL BORING machines that can produce square, figure-of-eight- shaped or elliptical cross sections will soon be available in Europe, a packed meeting of the British Tunnelling Society heard last week.

'Even triangular is possible,' said Kawasaki tunnelling department general manager Yasunori Kondo, whose presentation on 'Exotic TBMs' was described from the floor as 'the most interesting talk I've heard in nearly 30 years of BTS meetings'.

Kondo gave details of a wide range of advanced equipment unknown to European tunnellers. Some were already in use on projects in Japan, others are still at the prototype stage.

The square TBM now on trial uses a conventional rotating shield fitted with supplementary planetary-action cutters. However, more unusual cross sections will be possible with a new generation of 'parallel link' excavating shield machines. Here the shield oscillates rather than rotates, ensuring even wear across all the cutters and so longer maintenance intervals.

The first parallel link TBM to go into service will be circular, but Kawasaki hopes tunnel designers will take advantage of the new technology to economise on excavation by specifying more efficient cross sections.

Also in service are 'mother and child' TBMs, used for tunnels with branches. Normally a shaft would be needed to install a second separate TBM to bore a branch tunnel. Instead, Kawasaki's 'mother' TBM carries up to three 'child' TBM kits. These emerge at junctions and carry on independently.

A full report will appear in ICE News next week.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.