Taking that, these days, microtunnelling means ‘remote control tunnelling’ to most people, we asked Werner Suhm a few questions on significant development in the sector.
Suhm, qualified in mechanical engineering, has been involved in microtunnelling from the early days of applications in Berlin, and has worked for Herrenknecht for 15 years. During this time Herrenknecht has supplied over 750 microtunnelling systems.
Recent developments in the sector, according to Suhm, include the greater use of remote-control in diameters up to 3.0m. This enables long-distance and higher risk projects to be undertaken in safety. Typical applications include river crossings of up to 1200m length. "Technical developments in small diameters for longer drives and less risk include peripheral cutter drives," Suhm said. "These allow face access for cutter changing from inside in diameters from 1200mm. Outside of Europe, contractors are required to take on all ‘ground’ risks and are therefore keen to reduce risk in these ways.
"For difficult ground, such as sticky clay, Herrenknecht introduced high-pressure (300-400bar) water-jet systems about four years ago to cut clay into small chips, clean away mud and improve excavation of sticky marls."
T&TI asked about the current market importance of operated hire since it had been vital for some to break into the market. "We resolved not to offer operated hire at first," said Suhm, "but now we have to in some markets due to competitor pressure. However, we never compete with long-term, reliable customers. We also offer diameter-dependent components, such as compact jacking equipment with AVN systems so that contractors can adapt their own machines to project requirements."
"A major market problem," Suhm points out, "is a trend to what we call ‘americanisation’ of the market spreading to Europe, or the ‘hire and fire’ culture. Ten years ago a lot of companies invested in microtunnelling equipment, but these days no-one will invest without a big contract. Consequently, manufacturer service and rental is getting more important. The market is not generally healthy. It was technology driven for a long time, but now it is more price and performance driven. In some countries a poorly skilled workforce with a low price means that suppliers have to become more involved."
On the question of competing technologies, Suhm points out that Herrenknecht now offers directional drilling plant (maxi and mega rigs) to complement microtunnelling systems for similar diameters. "But it only competes in markets such as river crossings, oil and gas. Drives can be over 1.5km. In fact, we have the widest range of plant technologies for all conditions."
