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Latest Technical Update

Advantages reinforced 24 January, 2018 Behzad Khorshidi of McNally Construction discusses recent research on hybrid tunnelling by post-tensioning helical segmental lining > read more

Design Considerations 30 August, 2017 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 31 October, 2016 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 31 December, 2015 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 30 October, 2015 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 30 October, 2015 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 25 June, 2015 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 24 June, 2015 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 24 June, 2015 Rising interest in pumped storage hydropower in the US could see more large underground excavations in coming decades. Report by Patrick Reynolds.

Frozen fight 24 April, 2015 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 25 February, 2015 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.

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