Geology Reference
In-Depth Information
Figure 7.9
Collapse of fault
zone around
TBM
-
Tunnel Boring
Machine
ll
and grouting above
the tunnel.
Figure 7.10
Solution
sink
shaft in advance of
TBM and excavate
tunnel by hand
back to TBM,
allowing it to be
protected and
freed up.
-
Recovery shaft
Tunnel Boring
Machine
Recovery tunnel
because a fault was clearly indicated by the ground investigation. The
contractor agreed that there was a fault shown from the boreholes but
argued that the GI did not indicate the degree of disturbance that had
led to the collapse. Another expert was called to give evidence. He was
asked,
'
Was such poor ground an unusual occurrence with such
faults?
'
The expert answered,
'
yes, very unusual
'-
[case going the
It is so interesting
that I bring my students each year to examine it in the quarry near the
site where the collapse occurred.
way of the contractor]. He then went on to say,
'
'
Case dismissed.
[The New
