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SUMMER EDITION
Tunnel Vision: Should they Float or Bore?
FCUK is French Connection United Kingdom - pop fashion - but could also describe, literally, the Channel tunnel.
This week we look at an engineering strategy for this mega structure. (Yes, I got the idea from watching too many episodes of Megastructures over the break).
As you probably know, the Channel tunnel (the Chunnel) is a 50-kilometre undersea railway linking England and France.
After the second world war, Winston Churchill saw a UK connection with a united Europe as essential for geopolitical stability. (Thanks to David Cameron things have moved on a bit). Anyway, by the late 80s, the Chunnel was completed – the literal connection of the UK with mainland Europe.
Planned in the 70s, and completed in 1994, this is now a day to day bit of infrastructure. Like the Concorde, this was one of the most ambitious engineering feats in history and also a miracle of political and financial will.
But at the start of the project, the Chunnel engineers faced a critical question: what method should they use to construct the tunnel?
Two perfectly feasible paths emerged:
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Immersed tube construction, where a pre-cast concrete tube is floated to site and then sunk into place underwater (like the Sydney Harbour Tunnel)
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Tunnel boring machines (TBMs), where the machine grinds through the rock (like the scene in Oceans 13 where they are drilling under Bank casino)
Speaking of casinos, did they bet on speed and cost-efficiency with immersed tubes - or take a deeper gamble on the unproven potential of tunnel boring machines?
Which did they choose?
The Strategy Standoff
Strategy A: Float It and Sink It
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Like the Sydney Harbour Tunnel this proven method would keep the financiers happy and promise a faster, cheaper approach.
But contact with the sea floor could harm the environment and there would be longer term maintenance needs to control seepage.
Strategy B: Bore It Like Beckham
Use (then) new tunnel boring TBM tech to bore through the undersea rock.
A slower method, (and might get stuck like TBM Florence in the Snowy Mountains of NSW) but would offer longer term durability.
So, Which Did They Choose?
Cast your vote to find out!
Better luck next time, Strategy B was chosen!
Good Job, Strategy B was chosen!
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But what did this mean for the tunnel...
Outcome: Facilitator Commentary
Matt Braithwaite-Young
Managing Partner
t +61 2 9002 3100
A Deep Divide
The Channel Tunnel’s designers chose to use tunnel boring machines.
Immersed tubes were a tested solution for shorter crossings (but this is a long
crossing), while TBMs represented a leap of faith in emerging technology (and might not work at all).
In the end they chose to go for boring technology. Massive boring machines would drill through the seabed, creating a deeper, more stable tunnel.
The team tasked with delivering the Chunnel needed to think about the risk of cost overruns, potential for delays, plus the lifespan of the infrastructure and
environmental impact on the way.
Why did they zig instead of zag on this one?
The main reason is the chalky seabed under the English Channel provided an ideal material for TBMs, ensuring stability and watertightness.
And – predictably enough – political pressure to invest behind the TBM technology owners under the cover of protecting the (barren) English Channel seabed.
The Lesson: Know When to Dig Deep
The Chunnel’s success wasn’t guaranteed. The choice to bore rather than float
required balancing engineering foresight with financial pressures - and a willingness to take risks on emerging technologies.
Would you have chosen the faster, proven path of floating immersed tubes, or
gambled on digging deep with tunnel boring machines?
If you can’t see your options, BEWARE: they’re still there, just invisible to you.
Every firm, in every industry, faces strategy dilemmas. But clients sometimes feel like they don’t have options – usually, that's not the case but the options are invisible because leaders haven't yet allocated the time and space to think creatively about their options and direction.
As you can imagine, alternatives come to light pretty quickly in a crisis – for instance when a regulatory change comes, or a competitor launches with a new way of addressing your clients' needs.
Would it be wiser to think through your options before the crisis?
If you need a hand working through your options and aligning your team on options A or B, even the wildcard of "C" (careful of that one!), a Turning Leaf facilitator can guide you through a winning strategy formation process.
That's the sales pitch over. And if you actually read this far, why not call me or ping me an email today anyway... I'd love to hear from you and stay in touch. (Also, did you like these engineering and history versions, or should we stick to business cases?)
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