It’s always nice to kick off the month with some positive news and thankfully that’s definitely the case with April’s T&TI, courtesy of Section 2 of the UK’s Channel Tunnel Rail Link (see p6). It’s not often that we, as an industry, get the chance to wax lyrical about the success of a major urban underground construction project, so let’s make the most of it!

The 35km of 8.15m excavated diameter “London Tunnels” have been driven by six TBMs, through varying ground conditions, within the approximate US$1bn budget and ahead of programme! The construction teams tore apart the planned advance rates of 75m per week, hitting an average 100m per week across the six drives. The best 7 days were recorded at 282m of tunnel!

With the exception of a rather severe hiccup in east London, settlement rates have been negligible across virtually the whole alignment. So speaking from a technical point of view, all in all, the project gets the thumbs up.

There’s more good news from a safety point of view. No serious injuries were recorded during tunnel construction on CTRL 2. In fact, accident rates of less than a tenth of the UK construction industry average have been achieved on the long tunnel stretches. The UK construction industry’s five-year average for major works has an Accident Frequency Rate of 1.32, CTRL 2’s best tunnel contract weighed in at 0.11. The alliance, formed between the three tunnelling JV’s and the Stratford Box JV, has obviously paid dividends and more importantly shown that these ambitious projects are feasible.

In an era distrustful of what is regarded as the risky and pricey tunnelling option, the project could be used as a benchmark for future similar works, and an example that should instill confidence and inspire trust in those planning tomorrow’s infrastructure projects. It could certainly help with the business case for other schemes and will have done the prospects of London’s Crossrail tunnel no harm.

This is an international magazine and hopefully it is not considered too parochial to talk at such length about a UK project (even though it is on our doorstep!), but it is an achievement worthy of praise. So well done to the CTRL 2 tunnelling crews for a job well done!

Tris Thomas