Examination of Witnesses (Questions 2700
- 2719)
2700. So that it would be self-supporting, as
it were, self-propped. The difficulty with that is that you recall
at the beginning of the cross-examination that it is necessary
to construct the chamber, the adits and the passage, at underground
level, to go down to the Crossrail platforms, from this shaft,
is it not?
(Mr Morton) Yes.
2701. So if you prop by constructing the floors
as you go down you are then making it significantly more difficult
to excavate and construct the underground parts of the station,
are you not?
(Mr Morton) I think what
you would probably do is you would leave the final staircase out
until you needed it.
2702. I assume, Mr Morton, you are like any
engineer, in that ultimately you can always find a solution to
something. If you do put the floors in and leave the staircase
out you are making that underground construction a great deal
more difficult, are you not, because you have to have your digger
down at the bottom, getting the stuff into the middle and then
get it up a relatively small central hatchway?
(Mr Morton) But if you take
your clients' proposals you have to erect those floors and that
staircase within that shaft at some time. Presumably that would
be done, I imagine, as you go down—I do not know if it will
be or not. But you still have the same thing to do in a different
way.
2703. I think, Mr Morton, you may have missed
the point, with respect. You obviously have to put in the floors
and the stairs otherwise it is not much use as an emergency shaft,
but under our proposal you do that at the end when you had constructed
the adits downstairs. Under your proposal, in order to maintain
structural stability, you would have to put those in as you were
constructing the shaft.
(Mr Morton) As I have said,
you would leave the central staircase up.
2704. Just to come back to the point, that would
involve a difficult—not impossible—operation for excavating
underground and then getting out the spoil.
(Mr Morton) I do not think
that is again necessarily so. This is an engineering matter and
what you are doing is you have to put the floors in anyway and
if you do not put any floors in as you go down you have to come
back up and put in those floors. You have exactly the same situation;
you have a great deal of work to do to achieve that.
2705. I will try one last time. It is not the
same situation because under our proposal you do all the excavation
and the construction from the whole width of the shaft. Under
your proposal you put the full work of the floors in in order
to brace the shaft.
(Mr Morton) Yes.
2706. Thank you. Can we just look at what plant
and material you need for all three options, and can we have up
the plan that shows the construction plant that you need? Can
we go through the elements on this that one would need, first
of all for constructing by either method? This is our construction
proposal with number 38 removed. There is no issue that you would
need a crane on the site, is there? That should be document 37.
(Mr Morton) Before you go
on, could I go back one step to a question you just asked me about
the use of secant piles and the difficulties of doing that. I
see in the Mott MacDonald report that with the rectangular proposal,
which they obviously thought was a possibility, they actually
have secant piles shown.
2707. Mr Morton, have you read the Mott MacDonald
report?
(Mr Morton) Yes, I have.
2708. Do you remember it says, perfectly clearly
at 6.22, "Construction of a rectangular pile shaft is not
considered feasible for safety"?
(Mr Morton) It is constructionally
feasible.
2709. Are you proposing a rectangular pile shaft?
(Mr Morton) No, but I am
proposing to have a secant pile shaft, and they have shown it
on their drawings.
2710. Can we revert back to the plant on this
site, and what I hope you now have is P37. There is no dispute
that there has to be a crane on the site.
(Mr Morton) There does.
2711. Equally, there has to be space for a delivery
lorry to bring stuff on.
(Mr Morton) Yes.
2712. There has to be space to get the spoil
off the site.
(Mr Morton) Unless you put
it straight into the lorries.
2713. You have to get it off the site somehow
or other.
(Mr Morton) Yes.
2714. You can put it straight into a hopper,
as is shown here on the red hatching above the lorry.
(Mr Morton) Certainly you
could but it is certainly not unusual to load it directly onto
the lorry.
2715. There would not be in any benefit in space
terms in loading it straight into the lorry, would there, because
the hopper is above the lorry.
(Mr Morton) All right.
2716. I am not sure why it is necessary to argue
about that. So you have to have that space. Then it is necessary,
moving around the site, just taking the stuff for the construction
of the shaft, to have space for the lorry that is taking the spoil,
but you also need space for a lorry that is bringing in deliveries,
do you not?
(Mr Morton) Yes, you do.
2717. You then need to have some space, red
hatched here, for what is called materials lay down. You have
to have some space to put things that you are going to need in
the construction of the shaft.
(Mr Morton) Yes.
2718. Green here, you have to have some space
for welfare and stores, do you not? We are trying to make the
best use of the site so we have welfare above and stores below?
(Mr Morton) I am suggesting
both can go into the building if the building is left on site.
2719. First of all, you have to find somewhere
on a site for those two uses, do you not?
(Mr Morton) Yes.
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