INTERVIEW | DAVID FAWCETT


...THESE VERY COSTLY


BELT AND BRACES SOLUTIONS ARE WRONG...


there, the clay squeezes itself around it and seals it like a zipper.” More off-the-wall was a research project


he managed for the DoE (Department of Energy) investigating the feasibility of using tunnels to access North Sea oil. “It was in the early 1980s, and planting an oil rig in the North Sea was still pretty hairy. It was rough, it was the Wild West out there and people were losing their lives. The DoE commissioned the research in the faint hope of making it less dangerous. So they had this idea of tunnels.” One idea was to bring the oil and gas to


Above: Travelling and sailing is another passion. At helm in the Med. David has skippered more than 25,000 miles since retiring


land though tunnels. “To have any a tunnel carrying hydrocarbon gases – well, you could do that technically. I couldn’t see it happening, but my job was just to report on the viability of such a tunnel. So I reported that it could be done. Similarly for tunnels for taking people out to the rigs – that would have been safer than taking them out by helicopter. A friend of mine wanted a job out there, and was interviewed and got the ‘Don’t call us, We’ll call you’ treatment. And then they called him out of the blue and said ‘The helicopter carrying six engineers has just gone down with all hands. Do you want the job?’ That was how it was at the time; so even outlandish ideas got considered.” At least it wasn’t taxpayers’ money. “The oil companies were required to spend a certain amount of money on R&D, and they spent some of it on those reports. Of course they would never have spent money on actually building those tunnels.” On tunnel collapses his views make


Above: Jocelyn and David at the North Cape of Norway, on an Artic cruise in 2025 to the most northerly part of Europe


38 | May 2026


him a considerable outlier. A tunnel collapse causes tunnellers to hang their heads in shame and horror. It is more or less the ultimate sin in the profession. But if no-one is injured or is ever in danger Fawcett does not consider them to be all that bad. Consider, he says, the Glendoe tunnel collapse. Glendoe is a hydro scheme in Scotland, in the Highlands that was completed in June 2009 and it went into service, generating electricity. Two months later part of the main headrace tunnel collapsed. Generation ceased, and did not restart until remedial work was completed in 2012. “The original design was for a fully- lined tunnel constructed by drill-and-


blast excavation. During tendering it was proposed by a design-build contractor, who then won, that excavation should be by TBM, giving smoother walls of which only 40% need be lined. During construction it was decided that less than one percent needed actually to be lined.” After a few months of use, following take over by the client, some 71m of the tunnel collapsed at a geological fault line and was blocked by the rock fall. Extensive and expensive litigation followed, between the client, SSE, and the contractor, Hochtief. Then retired but continuing as a


consultant, Fawcett was brought in to advise the client. “SSE said that the entire tunnel should be lined. I said that that was unnecessary: it would take an additional 18 months, which is 18 months of lost revenue for you on top of the cost; and the tunnel doesn’t need it. You had been using it for three or four months before a small part of it collapsed, at a fault-line that was known about. You should have lined that bit. But you have tested the rest of it where there are no known fault-line, under different pressures, with no problems; so not only do you have a design, it is a design which you have tested and which actually works. So why put a full lining in? I came up with statistics to say they had a zero-point-two percent chance of any significant problems that would interfere with generation in the next ten years – they needed some sort of a number to take to their board. After a lot of persuasion, they went with my proposals for very limited lining. The tunnel is still operating well.” “I just think these very costly belt and


braces solutions are wrong, and need to be challenged. “It wasn’t appropriate in my opinion for


that client to line that tunnel even though it had had a collapse. I just think that, commercially, people get things out of proportion. Trying to get that sort of sense of proportion is where the effort comes in. “We should look at these things in


perspective; and, I also believe strongly that we shouldn’t just design something that is to some code. We should design what’s appropriate for a client, because the client might not need all the rest of it in his circumstance. “I think also that unless you have the odd


failure you are being too robust. People imagine that concrete is forever. It isn’t. Ask anyone who builds swimming pools – it gets attacked, it spalls, it degrades. The only thing that lasts (nearly) forever is


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