Hi, I'm Caitlyn and I'm a TBM Civil Engineering Apprentice
working on the HS2 project, mining the Chiltern Tunnels and
we're at the South Portal today and we're going to go into the
tunnel and we're going to go to the cross passages, the invert
bridge, and to the TBM to see what's going on in the tunnel.
So these multi-service vehicles (MSVs), or personnel cars, can carry
24 people including the driver. We just got off of
the multi-service vehicle(MSV) and we've arrived at CP2 (cross passage 2) in the upline tunnel, which is
where Florence is mining. A cross passage is a connection between
the two tunnels that we're boring, so we are going to be
mining from the upline to the downline tunnel. We're going to have 38
cross passages in total. We've been focusing on TBMs for a
long time so it's been all about Florence and Cecilia, but
now we have to focus on the cross passages too. So a lot of
the works that are going on will mean we have to split all of our
time and our logistics between cross passages and between the
TBM and itself. So we have to keep both of them working at
the same time and and keep the flow going. So now we're just
leaving tunnel one and we're going to go into tunnel two
where we're going to go to the invert bridge and we're
going to go see how we make our road tunnel.
So we're standing on the concrete slab invert bridge
right now and behind us you can see the TBM and we are not very
far from the TBM. This bridge is basically a bridge so we can
have the logistics going and we can also pour the concrete
underneath. It's a big machine that works very well to help us
get the logistics to the TBM without disturbances. So on the
one side we have the poured concrete slab which is being
done by the machine and it slowly advances forward after
it's done a concrete pour. It can advance about 30 meters
a day – it can do two pours. And the TBM can also advance 30
meters a day so it's a very convenient and very good
balance that works together. On the other side here you can
actually see that there is an invert which is just curved and
that curve will only allow one MSV, but on the other side where
we're pouring this concrete slab we're allowing it to have two
MSVs and more work to happen in the tunnel. Right now, we're
underneath the invert concrete bridge and this bridge is where
we pour all of our concrete to create that road in our tunnel
and above we have the actual bridge where our MSVs can pass
and still get the logistics to the TBM and personnel to the
TBM. So behind us right now is a concrete pour and they have
shoots just above where they pour the concrete in from the
concrete MSV, which sits on top of the bridge. They pour the
concrete in, they even it out they use probes and vibration
to make sure that the concrete is smooth and the correct
texture and then they have a finishing tool at the back
there that you can see and that just swipes across all of the
concrete to get the desired top texture that they want to have
for when we need the tracks to be laid.
So we've just got off of the MSV and we are on the back of
the TBM now and we're going to start walking to the front of
the machine where all of the major works happen on the TBM.
So we're at the front of Cecilia – this is as far as we
can go. Both Florence and Cecilia are just approaching
the first of the five shafts, at Chalfont St Peter.
This is where we're going to stop and they're going to do a bit
of maintenance to make sure that we can keep going and
continue after the shaft and keep building the rest of the
tunnel.