My name is Mark, and I'm the Tunnel Manager here at Long Itchington Wood.
Today we've just witnessed the incredible breakthrough of Dorothy,
completing the second one mile tunnel. It's been an incredible journey, a difficult journey,
made possible by the team effort of 400 people – of staff, the workforce and the engineers.
So now we'll have a look at the work that's got on behind the scenes to get us to this point.
Today we are at Long Itchinton Wood at the North Portal,
and we will be giving a look to Dorothy for the preparation of the second breakthrough,
popping a bit around the site, explaining what’s going to be happening in the future. Let’s go.
So we’re now at the segment yard. We’re using several types of vehicles – one is
for the personnel, which we’re going to go and board in a few minutes,
getting ready to move to the TBM. The other types of vehicles we’re
using are the MSVs – the multi-service vehicles – where we’re loading segments and grout
supplying the TBM for the logistics. We’re now at our tally hut, which is
controlling all the access to the tunnel. Paul is our tally man for the day and
he’s going to log our entry and deliver for us the safe set for self-rescuing.
So we’ve got our gear and we’re now moving to the TBM, which is about to breakthrough.
Our second tunnel was much faster than the first one. We has a lot
of lessons learned from the previous drive. Most of the workers stayed with us for the
second drive and are now delivering for us… All the learning of the crews was a very
good asset for us on the delivery of the second tunnel and helped us to deliver a
much better performance on this second drive. I’m happy to be in the cabin and being with
the crews, being able to adjust and see what is going on with the TBM,
because that remains to be my main focus. We’re getting closer and closer to the
breakthrough. I’m very happy, very happy that the second drive went much better.
So, we're at Long Itchington and we're here for the second breakthrough.
I feel privileged to be here today as well because I was here for the
actual launch of this, Dorothy, so yeah I feel great to be here.
You don't see many tunnel breakthroughs in construction and in the wider world,
so it's really exciting to be here today witness it happen and watch it with my team.
Today is an immensely proud moment for me, I mean it's a culmination of three years work.
It's very exciting, it's a big milestone finishing the
second tunnel and preparation for the for the future works.
So, when the machine is going to breakthrough, while passing the diaphragm concrete wall
we will be watching all the different parameters, mainly a lot of attention to focus on our slurry,
which is taking all of the spoils and all of the cuts from the front
to our slurry treatment plant in the surface. But as well we will be in control of all the
hydraulic pressures on the different cylinders, trying to control and make the breakthrough in
a very controlled manner. And ensuring that the head is fully in contact, the steering of
the machine is correct, so we are targeting straight in the middle, where we should be.
So, how do we control the steering of the machine? It’s a combination of different
things. The first one is our TBM pilots that are controlling the hydraulic pressure
on different cylinders that are pushing the machine and driving in different directions.
Every advance, as we’re building the tunnel, the ring is setting the
direction of the tunnel. The computer or the software is recalculating and anticipating
what will be the next advance after 2 metres. So the guys are adjusting the pressure here,
trying to match the red cross to be straight into the middle.
Here we are, straight at the front of our TBM, currently building a ring. And the
people are getting quite experienced now, with numerous rings being built.
So, they’re just moving an 8-tonne segment behind me and they will set it into position.
The process is now being fully controlled by the team, it’s a very specific process,
engaging a lot of safety aspects and requiring a high level of concentration for the crews. But
now they are a bit of mastering their stuff and being able to build rings in less than 20 minutes.
So we’re going to leave our crews finishing the tunnel.
The next time you’re going to see this machine will be on breakthrough,
from the South Portal, where there will be the cutterhead visible for the public.
It's an incredibly proud achievement to reach this point.
So this tunnel has taken four months we learned a lot of lessons from the
first drive and that's resulted in improved performance. We're now looking forward to
the challenge of taking the machine apart, and sending it to Bromford for its onward journey.
I'm absolutely amazed, it's fantastic to be fair. It's been a very long journey
and a good challenge, so happy, very happy really for the team.
It's definitely a moment I'll remember forever in my career.
So it's great to see it come out the other end – it's been a journey, seeing it go all the
way through, working on it while it's been in the tunnel – couldn't ask for anything better!