After more than six months of full-scale field testing on the construction of a 1,000-meter sewage tunnel, a geomatics-based survey guidance system for tunnel-boring machines shows promise for reducing interruptions in surveying while delivering real-time as-builts of the tunnel's interior.
"We can easily save 10% of total tunnel project costs," says Siri Fernando, engineering manager for the city of Edmonton, Alberta, Canada, which is using the tunnel-survey automation system called Virtual Laser Target Board (VLTB). Fernando is testing it on a $14-million, 8-ft-dia tunneling job. "We've seen good results the whole time," says Fernando, who is wrapping up the tunneling job in the next few weeks. The system's inventor, University of Alberta associate professor Ming Lu, was right in his claims last year of how much work time VLTB saves, Fernando adds.