ZED – TBM guidance specialists since 1975

ZED Tunnel Guidance has a long history in the main engineering disciplines of mechanics, electronics, optics and software which are now applied solely to tunnelling. Although a small company, the highly motivated staff are effective in utilising this experience in supporting the product technology, both at the factory and in the field. Development is a continuous process at ZED not only in refining the current equipment but more importantly providing engineering solutions to specific client needs.

As part of an integrated design process, where new or upgraded equipment is provided, backwards compatibility is usually maintained allowing older configured systems to be gradually improved in a more cost effective, stepped manner. Additionally, in certain situations when problems occur, the more complex configured systems can be downgraded, reducing capability, bypassing the fault but still presenting the TBM operator with basic guidance data allowing production to continue until the situation can be rectified.

Systems can be mounted on all types of TBM design and manufacture for hard and soft rock applications that permit line of sight to the cutterhead for a laser or reflector based reference. All diameters of TBM can be equipped with purpose-matched systems, from the largest to the smallest, operated either from onboard or a remote office according to available space. Complete modularity allows evolution to suit different projects, and all systems can be upgraded to more complex configurations.

Products vary in cost and complexity according to the job, and range from guidance systems designed for use on straight or simple tunnel alignments with large radius curves, to global coordinate based systems for more demanding projects.

North Side Storage tunnel in Sydney involved four TBMs ranging in diameter from 3.8 m to 6.57 m, each equipped with a ZED 261 guidance system. Despite the hard rock, the TBM vibration did not affect operation of the units, which survived the extremely harsh conditions in the tunnels and functioned perfectly.

The Yellow River Diversion project in China comprises 313.2 km of tunnel, much of which is being bored by TBMs of around 4.8 m-diameter equipped with ZED 261 guidance systems, working around the clock. The tunnels have to maintain an accuracy of 50 mm vertical and 100 mm horizontal, requiring accurate guidance.