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Geotechnical News • September 2014
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THE GROUT LINE
tions where a full cutterhead repair
was performed.
Conclusions
It is remarkable that for the first time
worldwide, a slurry shield TBM
advanced in closed mode at 14 bar for
hundreds of meters.
Several innovations were developed in
this challenging project such as:
• The setup of the procedure for
large-scale permeability tests and
their numerical interpretation
• Utilization of video cameras for
cutterhead inspection at high pres-
sure
• The design of new tools to drill
(probe and core) and grout injec-
tion under 14 bar of pressure
• Specific grouting procedures and
methodology
All efforts were carried out to avoid
saturation hyperbaric interventions,
which were considered too risky
in terms of safety, time and cost.
However we were fully equipped to
perform an intervention at 14 bar of
compressed air pressure which has
never been performed on TBM tunnel-
ling projects.
In conclusion, targeted and sequenced
grout campaigns with detailed custom
made procedures and methodologies
are effective even if conducted under
severe hydro-geological and ground
conditions.
References:
[1] Anagnostou G., Bono R.,
Donadoni N., Nicola A., Nicker-
son J., Schurch R., Zingg S. 2014.
Lake Mead/USA. Intake Tunnel
No.3 – A step beyond the limits.
[2] Nicola A., Donadoni N. 2013.
Lake Mead Intake No.3: assem-
blaggio TBM a 200 m di profon-
dità. In Proceedings Congresso
SIG 2013, Bologna, Italy.
[3] Anagnostou G., Cantieni L.,
Nicola A., Ramoni M. 2010. Lake
Mead Intake No 3 Tunnel – Geo-
technical Aspects of TBM Opera-
tion. In Proceedings NATC 2010,
Portland, USA.
[4] McDonald J., Burger W. 2009.
Lake Mead Intake Tunnel No. 3.
Tunnel No. 4, 43–48.
[5] Lombardi G., Deere D. 1993.
Grouting design and control using
the GIN principle. Int. Water
Power & Dam Construction, June
1993.
Jim Nickerson – Vegas Tunnel Con-
structors (VTC) Project Manager,
e: jnickerson@vtcjv.com
Renzo Ceccato – VTC Construction
Manager, e: rceccato@vtcjv.com
Roberto Bono – VTC Chief Engineer
e: rbono@vtcjv.com
Claudio Cimiotti – VTC Tunnel
Senior Engineer, e: -ccimiotti@vtcjv.
com
Pietro Fioravanti – VTC Grouting
Expert, e: pfioravanti@vtcjv.com
Figure 8: Three grouting campaigns.