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Infrastructure 2012: Bring on the tunnelling machines

Crossrail programme director Andy Mitchell is in festive spirit - the project is on the cusp of its most exciting
12 months yet.

Despite decades of talk, a couple of uncertain moments thanks to a recent change of government and tricky economic times – tunnelling for Crossrail will soon begin in earnest underneath London’s bustling streets.

The first two vast machines are scheduled to begin the task of snaking their way eastwards from the Royal Oak portal in west London in the first three months to form the twin tunnels to Farringdon.


There are a couple of jobs that need to be secured before though, which should make for an exciting end of the year. The final piece of the tunnelling contracts puzzle is imminent, says Mitchell. This relates to the vital C807 marine transportation contract that will enable much of the tunnel spoil to be transported out of London and onto Wallasea Island to help with the scheme turning it into new wetlands. On the shortlist are: a Bam Nuttall/Van OordUK joint venture; Carillion Capital Projects; a CemexUK Operations/ Keltbray joint venture; Lagan Construction; Port of Sheerness; and VolkerFitzpatrick.

Mitchell is also excitedly waiting for Christmas by when he has been promised his “perfect Christmas present” in the form of the arrival of the first tunnel boring machine (TBM) cutting head promised to him by manufacturer Herrenknecht.

“Crossrail is enormous but it is the year to demonstrate we’ve got this programme under control”

Mitchell has already completed much of the vital behind the scenes work – culminating in signing a “readiness to dig” form that signals that all the contractors running this part of the job are communicating and working well together and are all “comfortable that now digging this hole is the right thing to do,” he says.

It is without question an exciting and challenging prospect for Mitchell and the Crossrail team, partly because the workload doubles next year and there’s a lot to mobilise. But, without wishing to underestimate the scale of the challenge, Mitchell is keen to contain the excitement.

“Crossrail is enormous,” he says. “My ambitions may sound a bit modest but it is the year to demonstrate we’ve got this programme under control.” And while apologising for the pun, he adds that he’s “very keen” to have a “boring nine months” before noting that any previous occasion that the organisation has changed phase it has gone well.

“We’ll carry on but we’ve got to be realistic. There will be some days when one or two of our sites will be landlocked.”

Although there is one not-so-small exception to the likelihood of a “boring” nine months, and that is for some weeks in summer when that other London mega-project comes to fruition in the form of the Olympic Games.

So how do you carry out major tunnelling work under congested London when millions of extra tourists want to navigate their way from west to east, north to east, and any other way they so wish?

“It will be business as unusual,” says Mitchell. “But I’m pretty confident that we can work our way through it.”

Planning ahead

The Crossrail team has just finished an exercise that involved creating a day by day plan anticipating the situation on the city’s streets during the Games but says it’s difficult to say exactly what will be happening on a given date.

“We’re working closely with the London Organising Committee of the Olympic Games and Transport for London to get the clearest picture we can of what’s going on,” he says, adding that as the event gets closer there will be “fine tuning” to the plan.

“We’ll carry on but we’ve got to be realistic,” he says. “There will be some days when one or two of our sites will be landlocked.”

The Olympics is not the only challenge. While next year represents a huge step change, 2011 has also seen much activity. Diaphragm walling and dealing with utilities has been “inevitably more complex than I would like”, says Mitchell and there have been major constructions in the form of 13 shafts, which are either complete or underway. Compensation grouting exercises are also either in full swing or soon to start at some of these shafts and adits around London.

“The challenge is to do more about how we work together and use each others’ strengths”

One of the major factors in getting it right as these milestones present themselves is having the right expertise to negotiate them. And 2011 has been a year that has seen numerous major contract awards to get those people in place. Mitchell says he is “very comfortable” with the whole procurement process and that he was very impressed with the calibre of people and that the “key players” turned up and have mostly all got work from it.

While the winning bids were invariably well below the top end of each price band – which he recognises was much to do with being in a competitive environment – the team is also realistic that these are target prices and there is a lot that must be done to help bring that work in on target.

It has not simply been getting early contractor involvement but also optimising contractor involvement that is yielding great results already.

Leading by example

“There are ideas we couldn’t develop without involving consultants and contractors,” he says. One fine example of this process working has come with the “tricky piece of civil engineering” that is the Connaught Tunnel.

Because of this the OCI period was extended from three to six months, which gave the team time to look at its options and has led to a different construction method that now involves building a cofferdam to enable work in the dry to go ahead.

“It’s a little cheaper,” says Mitchell. “But there’s also a little less risk and it’s a less technically challenging method of construction. And it’s a great example of a benefit that can be had.

“The challenge is to do more about how we work together and use each others’ strengths to get better outcomes.” It is this philosophy, as well as a huge construction project, that he is keen will be extensively on show throughout 2012.








Key Crossrail milestones for 2012

■ January - Assembly of first tunnel boring machine (TBM) gets started at Westbourne Park Concrete segment factory (western tunnels) starts full production at Old Oak Common

■ February - Assembly of second TBM begins at Westbourne Park

■ March - TBM1 launched from Royal Oak to Paddington (Drive X) Construction of Stockley fl y-over underway

■ April - TBM2 launched from Royal Oak to Paddington First freight train carrying excavated material transported from Royal Oak to Northfleet

■ May - TBM1 to reach Paddington box Pudding Mill Lane site shuts down until conclusion of Olympics

■ June - Excavation of former Bethlehem Hospital (Bedlam) burial ground begins at Liverpool Street

■ July - First shipment of excavated material from Northfleet to Wallasea Island

■ Summer - TBM2 reaches Paddington Box

■ September - Piling works and diaphragm walls for Liverpool Street station box complete and main construction begins Pudding Mill Lane site resumes after Olympic Games conclude

■ Winter Drive - X TBMs arrive at Bond Street

■ During 2012 - Remaining central London stations main construction contracts awarded. These will be Bond Street, Tottenham Court and Liverpool Street as well as Custom House Rolling Stock bids invited Signalling contract awarded Major tunnel fit-out contract awarded Various over-site development applications submitted including Farringdon and Bond Street (Davies Street) Eastern tunnels segment factory at Chatham starts production First TBM launched from Limmo Peninsula to Farringdon (Drive Y).

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