A.E. Elioff, Senior Professional Associate Project Management, Tunnel Engineering, PB Americas, Inc. and
C. Laughton, Project Manager for Underground Design and
Construction at Fermi National Accelerator Laboratory
Paper
US Perspective: Challenges of Underground Facilities in Urban Areas
Presentation
US Perspective: Challenges of Underground Facilities in Urban Areas
Trenchless technology, often referred to as "no dig", is a rapidly growing engineering industry that eliminates the need for surface excavation. Trenchless technology is also used to minimize environmental damage and to reduce the costs associated with underground work. In other words, trenchless technology provides cost-effective sewer asset management. It involves pipe and sewer inspection, rehabilitation, and cleaning services.
"No dig" is exactly what it sounds like. There is no digging up of roads to replace gas and water pipes. When there is a need for pipe rehabilitation in the middle of a busy intersection, trenchless technology allows you to repair the pipe without having to dig up the entire road. Not only does this eliminate traffic problems, but it saves money because you do not need to repair the road that you would normally have dug up.
One of the most recent developments in trenchless technology is the use of robotics. One of the core benefits of using robotics is the measurable data it provides that allows agencies to better understand the state of their current systems. Robots are also able to enter hazardous environments that are too dangerous for people to access.
"Prague is the only capital city that has nearly completed a comprehensive network of tunnels which serve the most important parts of the city. The overall length is 90 kilometers. Compare it to Berlin - it has 25 kilometers, Paris has around 20 kilometers. It is not a problem to add any new wires or pipes - the system has been built to last for 200 years and to contain networks which don't yet exist today. Also, even before 2001 we implemented excellent security systems - of course, I'm not going to disclose any details. We have practically excluded the possibility of anyone getting into these systems. With gas pipes and so on, they could be potentially very vulnerable. It was an idea that no one else had had."
Visitors to the underground tunnels are equipped with overcoats and hard hats and a tour guide shows them round some of the most interesting parts. I asked Otakar Capek which utilities can be found there.
Otakar Capek says the utility tunnels or "kolektory" as they are called in Czech are a living organism which evolves constantly. In the deepest corridors, some 30-40 meters underground, a special train runs on five-kilometer routes transporting pipes, metal parts and other components. The tunnel is never complete; it is a never-ending process, says Otakar Capek and adds that this system, which he is so proud of, was mostly built during a historical period that tends to be looked down upon - the socialist era.
"Even in those days when there was a group of people who believed in something, who thought they were working on something meaningful, they could make it happen. The construction indeed had flaws of the socialist era. For example, after 1989 we had to renovate everything that did not meet safety standards. Such as fire doors made of cardboard, weak ventilators and so on."
"Prague is a tectonically stable area but the geology is very complex. You can find gravel sands here, clay, slate, etc., and all that poses many problems. When we were digging the big tunnel between the Municipal House and the bottom of Wenceslas Square, we basically followed the route of a 13th century ditch. It was full of objects discarded there and remnants of the old city walls which were later demolished. We worked with archaeologists and many of the objects that we found are on display right there in the tunnel."
Individual companies in Prague are now joining the venture which hopes to boost incoming tourism in the capital. When can visitors see the newly opened technological monuments? Jan Hauser of the Prague Chamber of Commerce.
"This would obviously be a question for the owners and the people who are running these sites but we hope that this summer, meaning the summer of 2007, should be the time when the first doors are opened."
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