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Going Underground | Longer, Deeper

Gotthard Tunnel

Society is increasingly demanding underground space to meet its needs.

As the engineering world marks another great feat with the opening of the world’s longest rail tunnel – the Swiss Gotthard Base Tunnel – now is the perfect time for New Civil Engineer to explore how infrastructure is Going Underground.

“This is a huge engineering achievement,” proclaimed ICE fellow and CH2M Tunnels and Earth Engineering Practice managing director Martin Knights as the 57km long tunnel was unveiled after a 17 year construction programme. “I’m pleased to see the vision finally come to life, and to see the project benefit from the major technical advances in tunnel boring machines made in the 1960s and 1970s.”

The appetite for boundary-pushing and record breaking in the world of tunnelling has long been the mark of the industry – as tunnel boring machines and the teams behind them shatter established limits in ever deeper, ever tougher rock over longer distances.

“Tunnel engineers are proud people,” said Swiss transport and environment minister Doris Leuthard a few years ago as work on Gotthard continued its journey.

“They are also pioneers. Tunnel engineers are among the last adventurers of the modern world of professionals.”

And it is not just tunnelling.

A desire to build caverns and basements in scale and quantity not seen before means, technical challenges need to be met, whether it is in seeking an answer to how to build deep geological storage to hide nuclear waste from where it can damage human life; or resolving how to make carbon capture and storage work on an industrial scale; or even perhaps creating low cost energy storage – the Holy Grail of renewables enthusiasts – by reviving disused salt caverns to store energy, thereby fixing the problem of intermittency. 

Tunnel engineers are among the last adventurers of the modern world of professionals 

Despite the obvious prestige granted to those tunnellers working on the world record beating projects it is not just vanity pushing them to go where no person has gone before. There is a simple pragmatic reason behind it all.

Space above ground is at a premium. There may be some who are a little sick of the word urbanisation and how often it is trotted out by economists, politicians and self-proclaimed futurists.

Amid the jargon lies a great global engineering challenge: How to provide vital and safe water, energy and transport systems with so many people congregating in metropolitan squalls. United Nations predictions suggest that by 2050 the proportion of the world’s population living an urban life will increase to 66%, up from 54% in 2014.

A good number will need to be accommodated in already congested cities.

As Leuthard put it: “Making use of the earth beneath us will become increasingly important in terms of transport and energy infrastructure.”

Singapore has firmly grasped this point of view. It is the third most densely populated country in the world and covers just 717km2.

So last year, the country introduced an edict to ensure state ownership of land below 30m depths.

“Singapore is a small country with scarce land resources, explained senior state minister for law Indranee Rajah last year. “There is therefore an important need to optimise all of our land resources, including the use of underground space, for the benefit of Singaporeans.”

The edict provides for private basement construction and deep piling but otherwise the land is available for the government to free up precious overground space for housing, parks and recreation by taking transport and energy systems well below ground.

The country does urbanisation in a way that many may seek to emulate. While its CO2 emissions are currently well above average for OECD countries, they are now falling. Globally, tunnels feature in a quarter of the top infrastructure projects compiled by management consultant KPMG (see box). It is a number that is increasing.

United Nations predictions suggest that by 2050 the proportion of the world’s population living an urban life will increase to 66% 

Governments and investors are waking up to offsetting the sometimes eye watering upfront costs of major tunnelling projects with the social and environmental benefits that the end product will bring. But tunnelling often remains a high risk endeavour.

The up to 11 bar pressure encountered 106m below sea level on the Eurasia Tunnel in Istanbul, alongside nervousness about high profile tunnel boring machine (TBM) problems – such as those that hit a Hitachi Zosen machine on the Alaskan highway in Seattle – put huge pressure on those involved.

Contractor Yapı Merkezi board member Basar Arıoglu told New Civil Engineer earlier this year that that pressure was coming from all angles, even from the boss of tunnel boring machine giant Herrenknecht: “Martin Herrenknecht was telling me, if this project has a problem like the one in America, then you can forget about the big TBMs for a while because nobody will insure them.” 

And then there is the ongoing challenge around tunnelling safety. In 2004, Singapore witnessed one of the most memorable fatal accidents in construction when the diaphragm walls of an open cut tunnel being excavated for Singapore Mass Rapid Transit’s Circle Line caved in, killing four construction workers.

While Gotthard is a technical engineering success, nine workers died during its 17 year construction. 

London’s mega tunnelling project Crossrail has also failed to complete its work without blemish – while the 2014 death of Rene Tkacik was ruled an accident by the coroner, he was killed while undertaking concrete spraying operations.

As London tunnelling expertise moves on to that other mega-project – the 25km long Tideway tunnel – there is a desire to try and improve things when it comes to safety.

As we learn from the special supplement with this month’s New Civil Engineer, Tideway is using the word transformational.

Its EPIC safety induction is designed to be impactful and no-one – according to Tideway chief executive Andy Mitchell – is getting near one

of its sites without having done the full one day induction – not even to change a lightbulb or fit a new filter on a crane.

The consequences when anything goes wrong in tunnelling appear multiplied, which demands that ever newer, better design, techniques, methods, people, equipment and technology are used.

Only then, and perhaps when robots are truly competent and reliable to take over, will the real potential of going deeper, longer and wider underground be fully realised. 

Global tunnels

Global tunnels

 

Tunnelling Awards

New Civil Engineer’s hugely popular Tunnelling Awards are back for their seventh year, and the 2016 event promises to be bigger and better than ever. The awards showcase the very best in tunnelling expertise, and the December event is now firmly established in London as a premier networking event for the global tunnelling community.

The awards attract entries from the tunnelling industry’s élite, and the judging panel is packed with world-renowned tunnelling specialists representing clients, consulting engineers and contractors – so to win an award is to truly excel.

Guests will converge on London in December to join key clients including London Underground, Crossrail, High Speed 2 and Tideway in a 500-plus audience with one thing in mind – who are 2016’s outstanding tunnellers?

As ever there is range of categories to suit the entire industry, from the biggest multi- national contractor to the smallest specialist supplier.

New categories for 2016 include the Community Engagement Award, Tunnelling Project of the Year (up to $50M), UK Tunnelling Team of the Year and finally Global Tunnelling Team of the Year.

With 14 categories to choose from and a free, simple entry process, it couldn’t be easier to put the best tunnelling achievements in the spotlight. Entries close on Friday 24 June 2016.

 

 

 

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