Shotcrete Profiles
Fibre Reinforced Shotcrete - Cross City Tunnel
Project, Sydney.
Structural Rehabilitation Works – Newcastle
Ocean Baths.
Mt.Owen Mine (R.O.M) Dump Station Project.
Shotcrete Profile 1:
- Project:
- Fibre Reinforced Shotcrete - Cross City Tunnel Project,
Sydney.
- Client:
- Baulderstone Hornibrook / Bilfinger Berger.
- Duration:
- (15 months) Proposed completion 2005.
Description:
Specialist Site Services was engaged to carry out
structural shotcrete stabilisation of the Darling Harbour
off-ramps, cut/cover sections, ventilation shafts, tunnel
rib and roof. The specification called for the application
of SFRS (steel fibre reinforced shotcrete) to all areas. SFRS
was used for stabilising all permanent / temporary excavations,
contiguous piling and the final lining of cuttings to a minimum
thickness of 75mm.
The sprayed areas consisted of mainly fractured/faulted
sandstone including ironstone seams with minimal ground water
ingress. Some ironstone seams that were sprayed with SFRS
included placing rockbolts and mesh.
Several means of shotcrete delivery were
required due to access difficulties such as piggy backing
a line pump on the surface direct to the shotcrete rig, lowering
kibbles of shotcrete down a vent shaft directly to the shotcrete
rig. The frequency of shotcrete deliveries from the nearest
batch plant was problematic due to the traffic congestion
of Sydney. The mix specification would not allow the use of
hydration inhibitors meaning our specialist shotcrete crews
were kept continually on alert.
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Spraying SFRS from a boom lift to seal
up areas of instability. This was carried out prior
to allowing the access of workers. |
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Cut and Cover section at western portal
to Cross City Tunnel. Ironstone seam required 3mtr CT
bolts and mesh prior to SFRS. |
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Shotcrete Profile 2:
- Project:
- Structural Rehabilitation Works – Newcastle Ocean
Baths.
- Client:
- Newcastle City Council.
- Duration:
- 1 week.
Description:
Specialist Site Services was engaged to carry out structural
repair work to the southern promenade of the Newcastle Ocean
Baths. The southern wall of the Ocean Baths had collapsed
during heavy seas. The heavy seas scoured out underneath the
promenade requiring the immediate closure of the baths to
the public. The Newcastle Council used excavators to remove
the damaged concrete wall enabling us to underpin the promenade
with shotcrete.
The design engineers specified stainless
steel reinforcement for the entire wall. The wall dimensions
were 50 metres x 1.6 metres x 0.8 metres thick, all requiring
shotcrete placement of 50mpa concrete. Shotcrete was specified
due to the continual flooding of the promenade by heavy seas.
Due to the thickness and the length of the wall it was sprayed
and float finished in 5 metre bays. The was carried out by
spraying alternative bays and curing with a wax based curing
agent. The entire project was completed to the satisfaction
of the design engineers and the Newcastle City Council.
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Placing 50mpa shotcrete Note: stainless
steel reinforcement. |
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Spraying of alternative bays and finish
of construction of ocean baths walls. |
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Shotcrete Profile 3:
- Project:
- Mt.Owen Mine (R.O.M) Dump Station Project.
- Client:
- Roche Mining(JR) Pty Limited.
- Duration:
- 15 Days.
Description:
Specialist Site Services were called in to drill, mesh and
shotcrete both wing walls adjacent to the dump station. The
scope of work called for the grooming of large areas including
the placing of strip drain and galvanised mesh prior to drilling
being carried out. All mesh was placed and stitched manually
by our shotcrete team working with retractable harnesses.
The reinforcing mesh was secured to both embankments by pattern
drilling and placing of galvanised dowels. All dowels were
fully cement grouted prior to placing shotcrete.
Drilling was carried out from a 120ft boom
which enabled our team to complete 2/3 of the work, the rest
was completed on foot in retractable harnesses. The same work
method was applied for the shotcrete, with the majority being
placed out of the boom and the rest by hand and harness. All
work was completed to the satisfaction of the client and within
the timeframe required.
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The dump station nears completion with
some fine tuning being carried out prior to shotcrete.
Notice drainage beneath mesh.
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The shotcrete team needed to spray
large areas from the ground. The slope angle proved
hard work for the shotcrete team.
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