Above: Another major project worked on was Storebaelt, in Denmark


end, I think it will be the huge differential pressure over the face as the TBMs get bigger and bigger that will be the limiting factor. I had the privilege to advise on both these projects. “It is stating the obvious to say that AI will


play a large role in the future. It can cover matters such as ring erection at the face, automatic addition of additives at the face of closed face TBMs, grouting and the like. The depth that TBMs can operate at will be no longer limited by the workers’ ability to work in high pressures. Instead of people down there, AI can be used to produce robotic working. “Construction materials will continue


to improve. This is especially true of things such as environmentally-friendly concrete and the use of carbon fibres. The industry as a whole, of course, is working hard to produce an environmentally-friendly concrete that takes less heat to produce. Concrete underground can also act as an emissions-free heat source. In building with deep piles in cities, they often put


the pipes for ground-source heat pumps into piles: they put the pipes in along with the reinforcement. That’s environmentally friendly. You can do the same thing with tunnels. You have the pipes buried in the segments, and you join those all together, so you have a source for the ground source heat pumps. I don’t know of any tunnel that has used such a system yet. It’s probably still at experimental stage but it would seem a very promising concept. “I think of the changes I have seen in


sixty years of tunnelling and am sometimes astonished. Instead of the huge and dirty muck waggons that we used to see there have been gradual improvements in the long conveyors, which are becoming more and more common in TBM tunnels. Welding has largely replaced rivets. There is virtually no hand digging at the face. “A very high percentage of tunnelling


in waterbearing ground is now done with closed face TBMs, slurry machines and EPBMs, both in their infancy when I started work. The New Austrian Tunnelling Method


(NATM), now called Sprayed Concrete Lining (SCL), had not been invented back then. The introduction of lasers to control TBM positioning was a game-changer – that was around 1962. More important than any of those is the Health and Safety at Work Act, which came in in 1958, the year that I started work. That must have saved many lives. “For the future, control systems will


continue to be ever more sophisticated. As with motor cars there will be an increasing use of a central electronic brain in TBMs. EPBMs and slurry machines will continue to improve. In the case of slurry machines this may be through a further development of the slurries and cleaning plants; in the case of EPBMs the use of foam will no doubt be further refined. “But the need for tunnels is going to


remain. When I compare in my mind the state of the art as it is today and what it was when I started work in 1958 I am truly amazed – so anything is possible for the next 65 years. Tunnels on the Moon are quite likely and maybe Mars!”


CHANNEL TUNNEL PAY - A MOVE FROM CASH If you want an example of just how old-fashioned things were just those few years ago, the building of the Channel Tunnel


brought about a major change in the law that affected all employment since. “The law as it existed back then said that every person had the right to receive their pay in hard cash,” says Biggart. “At peak eight thousand people were working on the Channel Tunnel, just on the British side. Trying to pay that number in cash each week would have been a nightmare for cashiers; so the powers that be went to the Government and said, ‘We’ve got to do this job properly. You will have to change the law.’ And they did. I think that was the beginning of the end for cash on site. “It meant of course that if they wanted to work on the job the employee had to have a bank account, and that was new for some of them too. So it was also a gift for the banks.”


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