Technical - Page 1
Stay up to date with the latest technical features from the global tunnelling industryLatest Technical Update
A Look Beyond Only Physical: Virtual Master Rings Florian Werres of VMT describes a digital approach to achieving the assurance of segmental quality for bored tunnels without always physically erecting master rings.
Structural design and classification of FRC for tunnel linings Axel G Nitschke, Tunnel Practice Leader at WSP USA, looks at the use of fibre-reinforced concrete and suggests a labelling and classification system designed to provide an effective and easy way to specify FRC for tunnel linings
Advantages reinforced Behzad Khorshidi of McNally Construction discusses recent research on hybrid tunnelling by post-tensioning helical segmental lining
Design Considerations ACI recently drafted a new report as the first design guideline on FRC tunnel segments to provide specific guidance for this emerging technology. Mehdi Bakhshi, Verya Nasri and Federica Mercuriello of Aecom discuss how to implement the ACI 544 Guideline into tunnel design
Efficient design of openings in SCL tunnels This paper by Dr. Angelos Gakis and Petr Salak, both senior tunnel engineers and design managers for Dr. Sauer & Partners, presents the case for SFRC being sufficient to support an SCL tunnel opening, without the need for additional reinforcement.
Unexploded ordinance Uxo (unexploded ordnance) can arise from both hostile and defensive military activity and is often related to World War I and II. Simon Cooke, 6-Alpha Associates, explains to the March 2015 meeting of the British Tunnelling Society how Uxo can pose a risk to tunnelling activities and how risk can be managed and mitigated to alarp (as low as reasonably practical), in accordance with the law and using best practice.
Maximum safety under maximum pressure A large road tunnel deep beneath a strait, a railway tunnel through an enormously complex mountain range, a water tunnel under tremendous ambient pressures: mechanized tunnelling is penetrating into new terrain underground. True partnership with contractors and project owners leads to pioneering developments in machine technology. Integrating knowledge from professional offshore diving also contributes to significant progress in tunnel construction. Herrenknecht's Werner Burger, head of engineering and member of the traffic tunnelling executive board and Georg Küffner, writer, elaborate.
Fit for purpose An expanded concrete lining was suffering in void-filled, desiccated Lambeth Group geology, before London Underground intervention to re-line the operational tunnel with SGI saved the day. Alex Conacher speaks to LU’s lead tunnel engineer and CDM designer/coordinator Neel Goorvadoo.
Face lift Manitoba Hydro embarked on a programme to construct a new seven bay, gated spillway to replace its existing facilities. Boro Lukajic, an independent consultant, and Brian Peter of KGS Group Consulting Engineers, describe the project, now successfully completed.
Tied together Tie-in works of a tunnel twinning project in northern British Columbia required drill and blast excavation of access tunnels leading to interconnection tie-in chambers that were excavated in hard rock to within 3m of the existing pressurised steel lined penstock. Mark Kellaway and Dave Young of Hatch and Hatch Mott Macdonald and Gordon Revey of Revey Associates, Inc., explains the geometrically complex excavation undertaken during a limited shutdown period when the penstocks were depressurized.
Pumping Below Rising interest in pumped storage hydropower in the US could see more large underground excavations in coming decades. Report by Patrick Reynolds.
Frozen fight Over the last four years, McMillen Jacobs Associates has designed retro_ t, replacement, or new icing shields for four railroad tunnels in the US. Joe Schrank, Heather Stewart and Gerry Millar all of McMillen Jacobs Associates, explain the installations.
Predicting settlements from conventional tunneling The Üsküdar – Ümraniye – Çekmeköy (UUc) project in istanbul, turkey is an extension to the metro on the asian side of the city, running 17km underneath a dense urban area. Some 8km of tunnels needed to be excavated through weak to medium strong sedimentary rock using conventional methods. In this article based on a paper presented at WTC Brazil, Sara Bech Padrosa and Nicola Della Valle of Tunnelconsult share some of the lessons learned from the settlement prediction methods employed.
Common Core In an effort to advance characterization practices for complex rockmasses, Jennifer Day, the 2014 Eisenstein Memorial Scholarship winner, Mark Diederichs, and Jean Hutchinson, all of Queen’s University’s Geological Sciences and Geological Engineering department in Kingston, have developed and tested several new core logging procedures that account for healed structures that are present in such rockmasses.
Austrian Tenacity NATM use as a tunnelling method is widespread. But disagreement rages over contract practices, definition of the process, and even whether it counts as a method. Gary Brierley of Doctor Mole Incorporated presents his views on the spread of NATM.
Hartbeat Updating the John Hart Generating Station requires a new underground powerhouse. Jesse Schneider of Frontier-Kemper Constructors, ULC, and Tony Dell of SNC Lavalin Power, discuss the proposed design and construction approach for the project.
Romaine Diversion To build a dam for the La Romaine project in Quebec, a joint venture of EBC-Neilson needed to build a river. Donald Proulx, vice president of heavy civil works and mines, business development proposals, for EBC Inc, based in Quebec reports
Tied together Tie-in works of a tunnel twinning project in northern British Columbia required drill and blast excavation of access tunnels leading to interconnection tie-in chambers that were excavated in hard rock to within 3m of the existing pressurised steel lined penstock. Mark Kellaway and Dave Young of Hatch and Hatch Mott Macdonald and Gordon Revey of Revey Associates, Inc., explains the geometrically complex excavation undertaken during a limited shutdown period when the penstocks were depressurized.
Old meets new THE MAYO B project (Figure 1) arose from the need of the Yukon Energy Corporation (YEC) to increase renewable power sources and meet system-wide load demands, while ensuring that diesel consumed to generate electricity was reduced.