Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | FEBRUARY 2017 | 11 Front line Tom Rushe TBM Shi Engineer, Shieldhall Tunnel Tom Rushe working in the Tunnel Boring Machine beneath Glasgow (pic credit: SNS) I t's a daily commute to work with a difference. Tom Rushe and his colleagues are part of a team of engineers working on Scottish Water's £100M Shieldhall Tunnel project in the south west of Glasgow - part of the biggest upgrade in the Greater Glasgow area's wastewater infrastructure since Victorian times. When complete, the 3.1-mile long tunnel will run from Craigton to Queen's Park and help improve river water quality and tackle flooding in parts of the city. The men are working on a massive, state-of- the-art Tunnel Boring Machine (TBM) to build the tunnel as it travels at speeds of about 30 metres per day excavating earth and stone and installing the lining of the tunnel in the form of massive concrete rings. Progress has been steady and the engineers have recently completed the first mile of the tunnel. Today, like any other day, the engineers' shiŽ starts at 7am and will run until 7pm when they'll be replaced by another team of men working the 12-hour nightshiŽ. The workers follow this pattern five days a week, as the machine tunnels away, night and day. AŽer they arrive on site at Craigton industrial estate the men receive a briefing from the shiŽ manager, including an overview of the type of ground they will be working in, and then head for the main entry point to the tunnel, a giant 20-metre-deep shaŽ. Once they are individually checked above- ground, and given their own tally or number, they climb down four flights of metal stairs, descending into what looks like an unfinished underground railway station but is actually the entry and exit point to the tunnel and TBM, for all men, materials and equipment. Covered by a sound-proofing roof to minimise noise inconvenience to local residents, the shaŽ is a vast industrial cavern which houses a small- gauge railway and is all rolling stock, cranes, ducting and pipes. It's the hub of the whole operation, the point through which everything passes. By the end of the project, about 250,000 tonnes of excavated material will have come out this way – more than 18,000 pre-cast concrete segments (each weighing 2.5 tonnes) will have gone in. At the bottom of the shaŽ, the engineers working on the TBM board a man-rider carriage on an electrically-powered locomotive which transports them, along with the concrete segments, to the tunnel boring machine. The locomotive also takes stretches of pipes, ducting and cable to be installed behind the TBM as it progresses slowly but steadily along its route. The electrically-driven TBM is 180 metres long - almost twice as long as a football pitch - but just 5.5 metres in height with a long, narrow gantry running along its side. That, combined with it operating deep underground, is what makes working in such an environment extremely challenging. l Tom Rushe works for the Glasgow Tunnel Partnership, a commercial joint venture between Costain and VINCI Construction Grands Projects called CVJV, which is delivering the Shieldhall Tunnel project for Scottish Water. l When complete in late 2017, the tunnel will be 3.1 miles long, more than five times as long as the Clyde Tunnel, and 4.65m in diameter, big enough to fit a double- decker bus inside. It is being dug at depths of up to 32m, or 105 feet l It will be the biggest wastewater tunnel in Scotland, with a storage capacity equivalent to 36 Olympic-sized swimming pools.