There are few machines as bespoke, unique and elaborate as a tunnel boring machine, which has become the main tool for excavating long, high-capacity tunnels, such as those used along the High Speed 2 route, particularly where using other drilling and blasting methods would be impractical.
Whilst there are common concepts and techniques used as part of a TBM such as conveyor rollers, cutting blades and tunnelling shields, most TBMs tend to have bespoke elements to suit the particular challenges of the large-scale projects they are typically part of.
However, finding the first tunnel to be constructed using this method can be difficult to ascertain, as many early tunnelling systems only had half of the functionality you would expect from a TBM but the initial genesis for this system began in 1825.
The Thames Tunnel was the first underwater tunnel ever made and was only possible due to the invention of the tunnelling shield, a temporary structure used to stop cave-ins whilst the permanent supporting structure was constructed.
This system was designed by Marc Isambard Brunel and used by him and his son Isambard Kingdom Brunel from 1825 until the tunnel finally opened in 1843. Whilst important in proving the concept, it was only the shield system that was used rather than a complete TBM.
The first complete TBM to have been built was the Mountain Slicer by Henri-Joseph Maus in 1846, after being commissioned by the King of Sardinia to construct a tunnel between France and Italy through the Alps.
However, despite the elaborate locomotive with its 100 mounted percussion drills was constructed, it was never actually used to build what became the Fréjus Tunnel, as the Springtime of Nations in 1848 led to uprisings in both Italy and France, and the tunnel was constructed using pneumatic drills a decade later.
The first TBM that was actually used in a construction project was Wilson’s Patented Stone-Cutting Machine in 1853 to construct the Hoosac railroad tunnel in Massachusetts. It was made of solid steel, used cutting disks and was an innovative machine closer to a modern TBM.
It managed to drill ten feet into the rock before it broke down, and the tunnel was eventually completed two decades later using pneumatic drills.
It would take until 1863, nearly 40 years after the Thames Tunnel began construction for the first TBM to be created that actually successfully tunnelled more than a few feet.
Invented by Major Frederick Beaumont, it was used for a trial run for a tunnel underneath the English Channel in 1875, and in 1882 after some improvements by Major Thomas English, drilled over 6000ft (1.84km) through chalk, whilst French engineer Alexandre Lavalley had similar success.
This would have been the first-ever successful tunnel bored using a TBM and potentially changed the course of history. However, cold feet from the British Military led to the abandonment of the Channel Tunnel for another century.
Ultimately, the first completed tunnel bored using a TBM was a ventilation tunnel that was 2.1m in Diameter and two kilometres long between Birkenhead and Liverpool under the River Mersey.
