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Latest Technical Update
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.