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Efficiency

History of Tunneling

Alice-India Garwood
by Alice-India Garwood on January 9, 2019

Tunneling has been a crucial part of construction since ancient times. But, how much do you know about the ways in which it has changed? What developments have come to make immense underground and underwater projects, from the London Underground to the Channel Tunnel to London’s new mega sewers, possible!

Thousands of years ago tunneling was a back breaking process. Ancient societies use their hands, and as civilisation developed, hand held tools to create ditches, dug-outs and tunnels.

One fascinating method of early tunnel digging was the heating of rock and stone, before pouring cold water over it to crack and break the rocks in to manageable and movable pieces. This primitive method of demolition has been developed and made more sophisticated in more recent history.

In Ancient History

One historic method of tunnel digging is known as the cut and cover method. This is a technique for building roads that has been around since Roman times and was even used to help in the construction of the London Underground.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: Science Magazine]

"The cut and cover method, used by the Romans, was even used in the construction of the London Underground."

The Roman’s were famous for their plumbing systems and this is how they did it.

Rather than burrowing in to the ground, trenches are dug and a cover is used to create the enclosed tunnel

How did we move away from hand digging?

In France during the 1600s, gunpowder was first utilised for the creation of trenches. Gunpowder continued to be used for hundreds of years as the most efficient method of tunnel construction.

"Gunpowder continued to be used for hundreds of years as the most efficient method of tunnel construction."

That is until, nitroglycerin, in the form of dynamite came on the scene. Dynamite is a far more powerful explosive.  Dynamite is still used today though mainly in mining.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: Micromine]

With this new, powerful explosive tool, the ambition of tunnelling projects was almost limitless. 

1800s

During the 1800s the Industrial Revolution was in full swing. Engineering and building projects were bigger and more ambitious than ever.

Alongside the implementation of dynamite we also saw the development of methods involving steam and compressed air to power drills. These drills were used to bore holes big enough to fit explosive charges.

Not only this, but everyone's favourite tunneling tool: The Tunnel Boring Machine.

Tunnel Boring Machines or TBMs are huge flat faced drilling machines with indentations and teeth to allow the efficient demolition of rock and earth in tunneling.

One of the largest tunnel boring machines in the world is Martina.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: Toto]

Martina is a hard rock TBM measuring 15.62m in diameter and 130m long. She was famously used to drill the Sparvo tunnel in 2011. The project took 2 years in total and spanned 2,430m.

The first ever TBM was used in 1825 by Marc Brunel and James Greathead in the construction of the Thames Tunnel (which would later form the basis for the London Underground). With this came the new challenge of tunnelling under the Thames river.

"The first ever TBM was used in 1825 by Marc Brunel and James Greathead in the construction of the Thames Tunnel."

Brunel and Greathead were also responsible for developing the tunneling shield.

Tunneling shields form a temporary protective layer as the shaft extends until a more permanent support could be put in place.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: ICE]

The shields worked in Brunel's time by having components that sat both horizontally and vertically. This allowed a worker to remove a plank at a time, dig a little further and replace the plank.

20th Century

There have been other striking developments in tunneling over the last 50+ years.

Known as the New Austrian Tunnel Method, or, the sequential excavation method is a form of tunneling that was first recognised in the 1960s.

The NATM is different from the old Austrian Tunnel Method because it relies on an understanding of the geological properties of the surface being tunneled in to. With constant monitoring, this is a flexible method of construction that allows room to alter the manner in which the tunneling is executed.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: Agru America]

Understanding the changes in the rock as the tunnel becomes deeper, altering the support structure and the speed as which tunneling is undertaken.

It’s pretty clever, super efficient and makes complete sense considering the complexity of tunneling.

21st Century

As drilling and tunneling becomes more efficient we can explore larger scale projects and, with this, larger machinery.

London’s future is being built from underground.

Tunelling, History, Construction, Supplies, Materials, Construction, Building, Methods, Bobtrade[Photo Credit: BBC]

Today work is being done to improve upon the original sewer system implemented by Sir Joseph Bazalgette. Improving upon this system means constructing a sewer system capable of handling the waste of more than 4x as many Londoners! The work will continue until 2023.

This project involves a huge TBM and the use of cofferdams at both ends of the London Thames.

Not only this but the on-again-off-again Bakerloo extension is back on the cards and with this comes the need for further underground drilling.

"London's future is being built from underground."

We look forward to bigger, badder and more monstrous tunnelling machines to take on the ambitious projects being pitched for London and the rest of the world.

Tags: Efficiency

AUTHOR
Alice-India Garwood

Alice-India Garwood

Content Marketing Executive at Bobtrade. Interested in design, sustainability and the history of construction. I love all things indie and theatrical.