Glasgow digs deep with £100m Sheildhall tunnel project

A city can't flourish unless built on solid foundations.

Tom Rushe at work underground on the Shieldhall tunnel project in Glasgow. Picture: SNS

That’s the guiding belief of a £100 million infrastructure development taking place beneath the streets of Glasgow, a massive undertaking largely unseen by anyone except for a few dozen contractors.

The Shieldhall tunnel is the biggest upgrade to the city’s waste water infrastructure since Victorian times, and the largest project of its kind attempted north of the Border.

A state-of-the-art tunnel boring machine is building the tunnel at depths of to 32 metres, or 105 feet, as it travels at speeds of about 30m per day, excavating earth and stone and installing the lining of the tunnel in the form of massive concrete rings.

The drilling machine has been named Daisy by a school pupil

When complete in late 2017, the tunnel will be 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 will be the biggest waste water tunnel in Scotland, with a storage capacity equivalent to 36 Olympic-sized swimming pools. The completed project will allow future housing and office developments to proceed across the Greater Glasgow area by greatly expanding the capacity of the Scottish Water system.

Construction of the tunnel in the south-west of the city involves excavating some 250,000 tonnes of material and installing more than 18,000 pre-cast concrete segments, each weighing 2.5 tonnes.

Engineers on the project work 12-hour shifts, starting at 7am or 7pm, with the tunnel boring machine working non-stop.

The drilling machine has been named Daisy by a school pupil

“It’s fantastic to be working on such an important project, the first of this type and size in Scotland, which will benefit Glasgow for generations to come,” said Tom Rushe, 25, one of those employed underground.

“I enjoy working in tunnels and, although it’s a challenge carrying out very technical work in these conditions, it’s one I relish and enjoy every day.

“You quickly get used to the confined space and we have everything we need down here for working long shifts – including a kitchen and toilet.

“Getting to my current place of work is certainly quite different to what most people do every morning above ground.

“But I would never want a conventional office job. Building tunnels is cool and I really wouldn’t swap it for anything.”

The centre of operations for staff is at the Craigton industrial estate, five miles south-west of the city centre. Engineers climb down four flights of metal stairs to the tunnel shaft, a vast industrial cavern which houses a small-gauge railway.

The railway transports workers to the tunnel boring machine. On their way, workers pass a small encased wooden carving of Saint Barbara - the patron saint of tunnellers, mounted on a shaft wall to keep silent watch over them in accordance with tunnelling tradition.

The electronically-driven tunnel boring machine – named Daisy by a local schoolboy – is 180m long, but just 5.5m in height, and has a narrow gantry running along its side.

That, combined with operating deep under ground, makes working in such an environment extremely challenging.

At any one time, there is usually a team of about eight working on the tunnel boring machine, driving or piloting it and operating equipment used to excavate material.

The finished tunnel will follow a route from Craigton to Queen’s Park, passing underneath Bellahouston Park and Pollok Park before tieing in to the existing sewer network.